Missing or Loose Keys
Keyboards get the brunt of abuse on any laptop, either from typing or spilled coffee. As a result, keys can often become dislodged or worn out. Thankfully, laptop makers provide quick online guides for replacing keyboards on their support pages; simply type "keyboard replacement" into the search bar or check the manufacturer's knowledge base.
For instance, Toshiba's "Ask Iris" document database provides hardware-replacement guides. To remove the old keyboard, you'll typically just have to remove some screws from the bottom of the laptop and unlock the keyboard with a button or snap mechanism, which secures it to the frame. Replacement keyboards are usually covered under warranty or can be purchased relatively cheaply.
Dell, for example, sells them for $15 to $25. The company also offers plastic keyboard protectors for $10 to $15 on its Web site. CompuCover offers keyboard protectors for a variety of other laptops.