Vista - Desktop Task Bar restarts when i open My Computer, My Docs, Contro

Recently i started getting a problem with my computer, I'm not sure if it is
a Virus or what. Anytime i open anything on the right hand side of the start
menu, the screen opens, disappears, then the task bar disappears for a few
seconds. I can run programs like WLM (windows live messenger), Itunes,
Firefox, and games too. It's just that i cannot enter my files or Hard Drive.
I scanned with Norton 360, couldn't find a thing wrong with my computer, same
with windows defender.
I have a vista upgrade installed and i use vista as the OS on a daily basis.
Another thing to mention is if i create a new user (not admin') the problem
does not occur. I tried copying my files over to the standard user, deleting
the other account and changing the other to admin', it worked for half a day,
then the problem returned. What is causing this, id really appreciate some
help, is it a virus, disk error, and even more important, what can i do about
it?


Computer Specs
Motherboard: Intel DP35DPM
Graphics: Nvidia Geforce 8800 GTX.
Ram: 4gb
Processor: Intel Core 2 Quad.
HD 1: 8gb with Xp.
HD 2: 150gb with Vista Home Basic Upgrade.

Id be really thankful of whatever help you can give me!!

-Conor Thompson