ITunes dead after System Restore

Question

I can no longer launch iTunes, and this has nothing to do with spyware.
Sequence of Events:
1) Last Thursday, I purchased a new track from itms (Iggy Pop - Candy - it's good, check it out).
2) Upon trying to play the track, I was presented with the message that the computer was not authorized to play the track. Other songs I tried to play gave the same error. I had been perfectly content using iTunes 4.7. However, in order to play the tracks, I now needed to upgrade to the current version of iTunes. This was, imo, obnoxious, but I capitulated, and downloaded and installed v6.0.1.3. After installation, iTunes worked perfectly fine.
3) Thursday evening I shut the computer down for the evening. I didn't use the system again until Sunday evening. When I powered the machine up, Windows booted to a black screen. Safe mode worked properly, but 'normal'-mode would not light the display (this is a laptop). Not knowing what was wrong yet, I tried using System Restore to return the system to a slightly earlier state. The most recent checkpoint was just before installing the iTunes update, so that's where I restored to.
4) System Restore didn't fix the problem. That's when I discovered the switch on the laptop that senses whether or not the lid is closed was broken, and it was telling Windows the lid was closed, resulting in the darkened screen. (I've removed the switch while I wait for the replacement plastic piece I need, so that's no longer an issue.)
5) System Restore did not have the option to undo the previous System Restore.
6) I then re-installed iTunes 6.0.1.3. Each time I try to launch iTunes, I see the standard MS "Do you want to send the error info to Microsoft?" message box, and iTunes won't start.
To try and repair the problem, I've tried uninstalling iTunes and Quicktime repeatedly. I've tried System Restore, and then a reinstall, several times. I've been a Computer Tech since '94, and routinely remove spyware problems from people's computers in a professional capacity. I am certain my iTunes problem is not malware-related. However, just to cover all bases I went ahead and followed the Apple doc referenced repeatedly in these forums involving MSCONFIG to ensure my iTunes problem wasn't related to some startup issue. I've taken the iTunes folder, with the library.itl and .xml files, and moved it to the desktop prior to reinstalling iTunes. I've uninstalled, and then deleted the Program Files\iTunes and Program Files\iPod directories prior to reinstallation. I've disabled my antivirus during the install.
No matter what I've tried, iTunes will no longer start.
Anybody have any ideas what I can try next to revive iTunes on my PC. I very much don't want to lose my existing playlists, album art, and music files (especially the approx. $130 of purchased music), obviously.
Thanks,
Steve
System:
Inspiron 8500
Windows XP Pro, SP2
Grisoft AVG Free Edition antivirus.

Answer 1

well done, NoahsMyBro!
hmmmm. some thoughts (speculation warning) on what might have gone wrong with the QT. a system restore "over top" of a fresh itunes install will strip out some installation registry entries from both QT and itunes. (under those circumstances, itunes won't launch, spitting out a "some of the required files ..." error message.)
under those circumstances, i usually recommend uninstall QT and itunes prior to the reinstall. (of course, you had other more pressing things to worry about at the time ...) i've been doing that because the QT component of the itunes installer bundle can be a little more delicate than the itunes component when it comes to installing "over top" of existing program files and folders. i think it's partly to do with the fact that it's the second install in the chained install (more can go wrong with it). so the QT may have been compromised on the reinstall, even though the itunes part of the install went through fine.
you don't tend to get the same QT install problems on a standalone QT install (again, speculation, but it seems plausible) because it's not the second install in a chain.
love, b