Itunes deleted my "Itunes Music Library.xml" file?

Question

Here are the facts (and then I'll pose the question):
-Ipod 80gb Classic
-Just upgraded to Itunes v. 7.4.2.4 (after following the pop-up window asking me to upgrade to the latest version)
-Windows XP Pro
-My "Itunes Music Library.xml" file and the "iTunes Library.itl" file are stored in "C:\Documents and Settings\XXXXXX\My Documents\My Music\iTunes" but all of my music/tv shows/etc are stored in another location on my HD
Here's the problem:
After I upgraded Itunes, the "Itunes Music Library.xml" file and the "iTunes Library.itl" file were replaced with brand new blank files (10kb and 32kb, respectively). When I open Itunes, the library is blank. All of the music files are still on my hard drive in the other location, but they do not show up in Itunes.
When I plug in my Ipod (which still contains all of the music), Itunes says "The Ipod "my ipod" is synced with another Itunes library...What would you like to do?"
Here's my question:
How do I get Itunes to show the proper content that is already on my ipod and on my HD? I just need my old Itunes music library files back.
Thanks in advance.

Answer 1

One point where this seems to occur consistently is if you reboot or turn off Windows while iTunes is running, and have a largeish music collection.
Explanation: Programmatically, iTunes main window apparently responds OK (=TRUE) to the Windows WM_QUERYENDSESSION message and at the same time starts to write the *.ITL and *.XML files to the hard disk. Meanwhile, Windows continues to end the session because - after all - it was OK'ed by iTunes. Now, if the iTunes music library is "large enough", Windows will finish ending the session before iTunes has finished writing said files, and the next time you run iTunes they'll turn up corrupt. This is a huge caveat during iTunes reinstallation, because most of the time a reboot is needed whilst iTunes will necessarily be running at the same time (consequently, if you have a largeish music library, always back up the *.XML and *.ITL files before reinstalling or updating iTunes!!!!)
This is nearly an elementary bug, and a sad indication of the level of testing done by the Apple to products before they're released.
Workarounds: I myself just frequently backup the *.ITL and *:XML files to a different directory, and restore if file corruption occurs. Another workaround is to have another program (say, Notepad.exe) with an edited but unsaved file currently open. When Windows session ends, you will have one extra chance to delay the session end, so that either you remember to close iTunes first, or if iTunes was closed first, it'll have enough time to complete writing the library metadata back to disk.
Asian and European phone giants have nothing to afraid about iPhone, if iTunes and iPod classic are any indication of its quality.