I believe I have a related problem to the related problem to this post (either way, this is the one topic that seems to most closely address my problem). I was prompted to upgrade my iTunes to 5.0.x (whatever the latest and greatest version is out now). I did so, it eliminated my previous version of iTunes, and after the supposed install, nothing happened (my screen went to exactly as it was before I clicked on the install link/program). I have quick links at the bottom of my screen, and I saw an icon being created, and then disappear. Parallel to that, I saw a directory being created, and then removed in my Windows Explorer. I have no clue what is going on now. I hope that someone is able to help me.
I do have anti-virus on my computer, but it doesn't seem to make a difference as to whether it's enabled or disabled. I have Windows XP/Service Pack 2 loaded. Not sure what else I might need. It's weird - I've never seen a program just stop in the middle of installation, and undo everything it has done. I have emptied out my Temp directory, and that didn't do anything. Basically, I've done all I know to do - I'm hoping someone out there has the answer I'm looking for. Like another poster said, I have numerous music files that I've paid for, and now I can't listen to. If anyone has an answer for me, that would be most appreciated. Thanks...