Pointer frozen - Mouse driver software missing

has anyone experienced this before?

My mouse froze two days ago. The mouse is fine, another
mouse does not work on the computer, and I find that the
mouse driver softwrae is missing.

Q: Where is the mouse driver software stored/how do I
reload it?

More info -
-I reloaded the mouse software somehow, using the XP cd
and Windows Support Tools Wizard, but the problem
returned. Did a Norton scan.
-An error came up when loading the Tools Wizard (through
Norton)that a malicious script was detected (file -
MS:Exec.exe)