or, “HELP11 SHIFT IS STUCK ON1″.
If you do not have trouble typing, nor holding down shift while pressing other keys, then you probably don’t need Windows XP’s Accessibility features. If you habitually tap the shift key whilst you consider your next sentence, for example, then you are definitely better off without them.
Tapping shift in this way is the activation shortcut for Stickykeys, which helps one-fingered typists by making the Shift key latch on until the next key is pressed. When you activate Stickykeys, it usually pops up a dialog box asking whether you want to activate it. The problem is, if you say no it still messes with your keyboard state and you seemingly no longer have control over your shift key.
Part one of extricating yourself from this is to get the keyboard in a sensible state again. Pressing and releasing the shift key (try the left first, then the right if that doesn’t work) should get back your normal behaviour.
Part two is to get rid of the shortcut so it doesn’t happen again. Unfortunately there is no button marked “nobody who uses this computer needs special accessibility functions” so we have to turn the features off individually:
Start Control Panel and open Accessibility Options.

Uncheck each of the “Use (something)keys” checkboxes as shown above. Then, to turn off the shortcut, click the first Settings… button to get a second dialog:

Uncheck the “Use Shortcut” box in this dialog and click OK.
Repeat the above step for the other Settings… buttons, then when all three are done, click OK to dismiss the Accessibility Options dialog.
Now you can play drums on your shift keys again, much to the delight of your colleagues.