I have a Dell Inspiron 1501 laptop since September 2007. Long time ago the Windows started to behave as some unknown key is being pressed every second or so.
For example, no bubble help remained visible for more than a fraction of a second. Images displayed fullscreen in Irfanview get back to windowed display after a second. Trying to set new key shortcut in some application almost impossible. Etc.
Detailed info about this cause and possible solutions:
Generally, BIOS update to latest version, and removing battery and pressing the power button for a few seconds worked for some people. Not for me.
KeyTweak showed that this phantom (ghost) key has number 57357.
So because I have still 30 days warranty left, I am sending this case to the technical support requesting to solve the problem.