iTunes lost my music

Recently, I updated my itunes, and when I tried to start it up, it said that I had to reinstall quicktime. Thats fine, I uninstall quicktime, reinstall it, start up itunes. Then, all my music is missing. Playlists are gone, music is gone, applications are gone. Luckily, I consolidated my library onto my portable hard drive, so I access that, and discover that half of the folders in there are empty, namely all my Disturbed and Metallica songs.

Infuriating doesn't even begin to describe it.

I had about 1200 songs, give or take a couple hundred, and the most I can get right now is 451, with an insane amount of duplicates for some reason. I tried accessing an itunes music library.xml from a couple weeks ago, and that only came up with 260 or so songs. I'd just ditch itunes and use WMP, but I've got an iphone.

Also, is it possible to move everything on my iphone, onto my computer?

 

the XML file I referred to wasn't from a system restore, it was just one of the itunes libraries I found in the itunes folder.

I did try a system restore back 2 weeks, then 3 weeks, and each time itunes wasn't working [required that i reinstall quicktime], and when I did, there were only 400 something songs, a large amount of them doubles.

I tried plugging it in to access it like a flash drive, but it just comes up as a camera and I can only access the pictures I had on it.

EDIT - Forgot to mention. For some reason, and this is fairly recent, when I start up my AVG anti-virus program, it won't scan my hard drive, so it might be a virus. Re-installing AVG to find out.

 

Reinstalled AVG, in the midst of scanning, and it's found 107 spyware and trackers and it's not done yet.

Also, found a program called ImTOO iPod Computer Transfer that works FANTASTIC. Started it up, plugged in my iphone, and the list of songs immediately popped up. Selected them all, and am coppying them to my hard drive.