Vista - Missing idlist file causing problems

My computer has been acting up for two days. The taskbar and desktop appear
and disappear randomly, taking with them any computer file I have up, like
the Control Panel, or a Search, or whatever. I have attempted malware
removal, virus and adware removal, and a sytem restore. Nothing works. I have
to use the Task Manager to start programs. When I ask it to run something,
though, a Windows popup will say 'The file '/idlist.:0:6034:,' cannot be
found (those numbers are random; they seem to change every time, but the
idlist is correct). Does anyone recognize this problem, and know how to fix
it?