Here's the problem. I hit "Shutdown" on the start menu. A few seconds later a dialogue comes up that says "Explorer.exe is not responding" with the count down timer thing. It's the same dialogue you get when a program isn't responding. I have to hit "End Task" before it lets the computer shut down. This sounds like a simple question, but it really isn't I don't think. Let me know if you can think of anything.
PS - My computer has been cleared of all virii and spyware. I have done a "Hijack This" test, and found nothing suspicious running in the background. I checked all startup processes contained in the registry, nothing suspicious there. Thank you for your help
AMD Athlon 2300+
120 GB SATA Maxtor 61Y20M0
NVIDIA Geforce 6800 GTOC
Sony DVD-RW DRU-710A
1 Gig RAM
Windows XP SP2 with all the latest and greatest updates