If you've ever pressed the Shift key five times in a row, intentionally or accidentally, you've no doubt encountered the Sticky Keys feature. It's designed for users who have special needs, and it makes certain keyboard functions considerably easier to access. You might find that you prefer it.
Suppose you want to launch Windows Explorer via the keyboard shortcut. Normally that means holding down the Windows key and tapping E. The same goes for common functions such as Copy (Ctrl- C), Undo (Ctrl-Z), and even capital letters (Shift-letter). With Sticky Keys enabled, however, you don't have to press two keys simultaneously. Instead, the Alt, Ctrl, Shift, and Windows keys become "sticky," meaning that you can press one of those keys, release it, and then press the other key you want to use.
(For more solutions to perplexing PC problems, see "The 21 Greatest PC Mysteries--Solved!")