How to Dual-Boot Windows 8 While Keeping Windows 7 As Your Default OS

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Windows 8 Dual Boot

Microsoft's upcoming Windows 8 operating system is available in beta "Consumer Preview" edition as a free download, but that doesn't mean you should stop using Windows 7 as your main OS just yet.  Here's a simple way to install the new beta operating while making sure that your computer still boots into Windows 7 by default.

Download the Windows 8 ISO File

Though Microsoft provides an executable file that downloads Windows 8 for you as it runs, we recommend grabbing the entire 2 to 3GB ISO file from Microsoft's site. If your current version of Windows is 64-bit, grab the 64-bit version or 32-bit if that's what you have now. Also, make sure to write down the Product Key on Microsoft's site as you'll need it during the install.

Windows 8 ISOs

Create and Install USB Drive or DVD

If your notebook has a DVD drive, it's easy enough to burn the ISO file to disc. However, many computers no longer have optical drives and many users no longer have blank DVDs lying around. You can turn any 4GB or larger USB flash drive into a Windows 8 install disk by using  Microsoft's USB/DVD Download tool. Simply plug in a blank USB Flash Drive and launch the tool.

  1. In the USB/DVD Download tool, choose the ISO file you downloaded and click next.

    USB Download Tool 1 

  2. Click USB device.
    Select USB Device 
  3. Select the drive letter of the USB driveyou wish to copy the install files to and click next.

    Select the Install Drive

After several minutes of copying files, your bootable Windows 8 USB install drive will be ready for use.

Create a Windows 8 Partition

In order for Windows 8 to dual boot with Windows 7 on the same computer, each operating system must be installed on a separate partition, with the Windows 8 partition taking up at least 20GB. If you're like most notebook users, chances are that your notebook's drive has only one usable partition, but fortunately you can create new ones.

  1. Type "Create and Format" into the Start menu search box and select Create and Format Hard Disk Partitions. The disk manager will launch.

    Create and Format Your Disk 

  2. Examine the list of partitions on your hard drive, looking for secondary partitions you can use for Windows 8. Ignore recovery partitions and partitions that are smaller than 20GB and chances are that you'll need to shrink your main partition and create a new one. If you do find a secondary partition you can use, you can skip the following steps.
     Examine partitions in disk manager
  3. Right click on your main partition and select Shrink Volume. A dialog box appears which asks you how much space you'd like to shrink.
     Select Shrink Volume
  4. Enter at least 20,000 MB (20 GB) as the shrink size and click Shrink. If Windows doesn't allow you to enter 20,000 MB or higher, try clearing more free space on your drive. If you have more than 20,000 MB free on  your patition but Windows still won't let you shrink to that size, download and use a third party partition resizer like Partition Wizard Home.
     Enter Shrink Size
  5. Right click in the unallocated partition then select New Simple Volume.

    Create a New Simple Volume 

  6. Create the volume with the maximum amount of available gigabytes. Select NTFS for the file format and name the volume something you can remember such as "win8."
     Give the new volume a size of 20,000 MB or higher.

Run the Installer

 Installing Windows 8 onto your Windows 7 computer is pretty straightforward.

  1. Boot off of your Windows 8 USB drive or DVD. Most PCs allow you to choose a boot device by hitting a function key when you power on.
     Boot Off Your USB Key
  2. Click Next then Install now. 
  3. Enter your product key when prompted. 

    Enter Product Key 

  4. Accept the license terms and click Next.
  5. Select Custom install.
     Select Custom Install
  6. Select the empty partition you created or found. If none is shown, go back to Windows 7 and make sure you have a blank partition that's at least 20GB.
     Select Partition
  7. Wait patiently as Windows takes a few minutes to copy files and restarts itself a couple of times. 
     Windows Copies Files
  8. Click "Change defaults or choose other options" on the start screen that appears.
     Choose Defaults
  9. Select "Choose a default operating system."  then Windows 7. 

    Choose Your Default OS 

  10. Change the timer if desired. If not changed, the system will boot to your default OS, which is now Windows 7, after 30 seconds of inactivity. You can lower that time for quicker, unattended boots.
  11. Click Windows 8 Consumer Preview to boot Windows 8 and continue the installation process.
  12. Give your PC a name (ex: DansPC) and background color. The name cannot have spaces or punctuation.
  13. Pick your wireless or wired Internet connection and enter any appropriate passwords.
  14. Select "Use express settings" to proceed more quickly.
  15. Enter a valid email address that's associated with a Microsoft Windows Live account or use this opportunity to create a new account.Microsoft will also ask for your phone number so it can SMS message you if you lose your password.

Changing Your Default OS After Installation

If you want to change your default operating system after installing Windows 8, you can still do so whether you are working in either Windows 8 or 7. 

  1. Hit Windows + R or type "run" in the search box. A dialog box appears.
  2. Type msconfig and hit OK. The System Configuration application opens.

    MS Config Run

  3. Click the Boot tab.
  4. Select the OS you want as default and click Set as default. You can also set the default timeout.
     Set the Default OS in Windows 8
  5. Click Ok.
Author Bio
Avram Piltch
Avram Piltch, LAPTOP Online Editorial Director
The official Geeks Geek, as his weekly column is titled, Avram Piltch has guided the editorial and production of since 2007. With his technical knowledge and passion for testing, Avram programmed several of LAPTOP's real-world benchmarks, including the LAPTOP Battery Test. He holds a master’s degree in English from NYU.
Avram Piltch, LAPTOP Online Editorial Director on
Add a comment
  • miami Says:

    thank so much it really

  • Thimmappa Says:

    thanks to u sir

  • Imran Ali Says:

    Can i make bootable external hard drive or USB at a time with windows xp,windows 7 and windows 8 help me with details if it is possible. if it is impossible can i make bootable with two windows 7 & windows 8. If you solve my problem i shall thank full to you.

  • Insall Windows 8 ? Says:

    Dual boot is possible. However, I am bit confused about the performance of the system. My friend now has a windows 7 and Windows 8 on his laptop. Now he is complaining about receiving error messages and freezing. I do not know if this happens just because he installed Windows 8.

  • ansul sahu Says:

    I have a laptop with windows 8 OS it is installed in C drive,and i also installed Ubuntu 12.10 Linux OS in G drive.
    but at booting time only windows 8 OS are booting.
    how i fix this problem.

  • Mike Says:

    I successfully, sort of, installed Windows 8 as a dual-boot. I selected my D drive, which had tons of space on it, to install Windows 8. After the install process I switched back to Windows 7 as my primary OS.

    Now here is the problem--I had put many of my applications on the D drive. After the Windows 8 install I can no longer "see" the files in the Program Files directory. The apps still run but their appears to be no files there. For instance, the icons for the apps are now broken.

    Anyone have an idea on how to fix this? Why did this happen?

  • christine Says:

    i have w7 on c and i created a partition I for W8 and chose custom and selected I but at some point I see it saying copying files to c:\... then W7 won't boot and I have to use the Recovery disk to get W7 back. I am wondering if I can change Win7 to be a different drive letter?

  • raulsoto Says:

    maybe is using upgrade option not custom install
    thats why the option of select operative system doesnt appear.

    this tutorial is well done. because its with images and information
    regards. now im downloading win 8 enterprise with free 90 day trial. and i make a second partition with 25GB.
    shrink on disk management cant give you more space sometime, thats i used a free partition program:
    Minitool partition wizard home edition v7.5 (its very easy too use and fast. i recomend it to you.
    make a partition for files and documents, and a new one for windows 8. then you will have 3 partition,
    one for win7, other for win8, and the final for files and documents.

  • debojit Says:

    hold on a sec. Your win 7 was in drive C and you installed win 8 in drive E. then why in msconfig of windows 8 showing the opposite?

  • Anorici Velekiste Says:

    Will the Win8 installation work if I use a Win7 PC to do the USB drive iso image writer then boot it thru a WinVista PC? Also, will Win8 work if I only have 2.0GB RAM, a Intel DualCore E2220 processor and a 25GB HDD Partition? Thanks, Anorici

  • Hap Says:

    I have a dual boot Win7 - Win8 by only having 1 disk in at the time of installing Win8 and replugging the other disk after installation.
    But, . . . each time after running Win8 and returning to Win7, the system wants to check all disks for errors.

    I know there is a small difference in file systems between Win7 and Win8, but does this cause the constant need for disk checking ? Will your system/method of installng avoid the disk checking ?

  • Ryan Says:

    If you follow this guide exactly as described. Writing it to a DVD or USB Stick, Restarting your computer and selecting to boot off USB or DVD, then run the installer you should get a Custom option. HOWEVER
    If you run the installer while you are in the windows 7 operating system, it will do an "Upgrade" which is why no option is present.

  • Gael Says:

    Windows 8 picked C: as drive letter fot its partition.

    Now boot loader loads Windows 7 but the partition containing it is assigned drive letter D: instead of C: which results on Windows 7 boot error: winload.exe not found.

    Does anybody know how to fix this without loosing my Windows 7 installed programs and data? (Don't care about Windows 8, it's buggy and too uncomfortable for me without a touch screen anyway...)


  • Charles Says:

    Pls after I installed windows 8 on my pc on the newly created partition I didn't get the Option to choose default Os. Now when I boot it goes straight to the windows 8 Os although the 7 wasn't tampered with. I tried msconfig and there is no option of windows 7 as an Os. Pls ur advice would do a lot of good to me. Tnx a lot.

  • Avram Piltch, LAPTOP Online Editorial Director Says:

    @LAWRENCE You have to make sure you have a free volume that's at least 20GB. We've tried this several times at the LAPTOP office and it worked every time. I'm not sure why you wouldn't see a "Custom" installation option. Maybe it doesn't work if you already have Vista installed as well; we didn't test with Vista.

  • LAWRENCE Says:

    The Windows 8 fiile downloaded to the DVD without a hitch. I find that there is no option listed as to where to install Windows 9. I do not wish to risk the chance that it will overwrite lhe present operating systems so aborted the installation. I am running a dual boot system with Vista and Windows 7 and have allocated a formatted space with a designated letter on the hard disk to download Windows 9. Also, it appears that Windows 9 does not accept Windows Defender as well as Vista's Window Media Player (or parts of it). I was hoping to give it a try but am now reluctant.
    The instructions worked great up to selecting the option of the non-existant "Custom" installation.

  • Kelly Says:

    This works well! Follow the steps & nobody should be losing anything even if you wipe a volume by mistake, that's why you make recovery discs & backup before attempting something like this!

  • John L Says:

    Mike D

    Had the same problem with product key. However solved when I copied the product key where you see it in the download. Then Paste it in the product key box

  • Sam Says:

    Its the same with mine. If you go back to the original OS, is will be as though they have switched. It's normal.

  • William Says:

    Weird, I tried it again and same result: Win 8 installs to the 2nd partition, but it removes C: from the 1st partition...and renames the 2nd partition C:

    The 1st partition is then greyed out in Disk Management. If I add a drive letter back to it all the files are gone as thought it's been formatted. , it's as though Win 8 corrupts the 1st partition and 'steals the 2nd.

  • Sam Says:

    Never mind, I redownloaded the ISO and it worked.

  • William Says:

    These instructions don't work!

    I didn't get a the screen with drive choices for install, it went directly from the Custom screen and did a full install.

    Yes it ended up installing to the new partition (D:) by default, but also wiped my C: and made it inactive. I lost my entire Win 7 volume!

  • Sam Says:

    After selecting the Windows 8 ISO on the Windows 7 USB/DVD Download Tool, and clicking next, I get a message that says the following: The selected file is not a valid ISO file. Please select a valid ISO file and try again. Any suggestions on how to get around this problem?

  • mike d Says:

    When I get to the product key and enter my Win7 product key it tells me: "The product key entered does not match any of the Windows images available for installation. Enter a different product key." so I downloaded a program that tells me which key is entered into my computer and both key match. So I'm typing in the correct key for sure but I keep getting this error. I called Microsoft and they couldn't help me. I tried live chat support and they couldn't help me. Hummm... windows 8 is getting off to a great start for me... not! Any help?

  • Robert Kolker Says:

    That's the funny thing: it's not giving me the option for a custom install. I have the partition ready. I run setup. It asks if I want to import my settings, etc. It then tells me what programs are incompatible and asks for me to uninstall them, and then asks for a reboot. Maybe the custom install option will appear after the reboot, but I'm worried that it won't and Windows 8 will overwrite 7.

  • Avram Piltch, LAPTOP Online Editorial Director Says:

    Did you choose a custom install and do you have a free partition that's 20GB or larger?

  • Robert Kolker Says:

    My setup disk does not seem to give me the option of choosing where to install windows 8. It tells me what programs need to be uninstalled and then asks me to restart the computer. I'm nervous that it will write over Windows 7 without giving me a choice.

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