Itunes will not recognize music in folder

Question

On my computer I have all my music in the itunes folder like it is supposed to be. After I import the music itunes will recognize it for a while but after a few days it will not recognize the music. Itunes says it cannot locate the file even though it is in the same place and has not changed in any way. All my files are MP3. I had this problem after my computer crashed earlier this year so I thought it had something to do with that along with some other problems. So when I had to completely reinstall Vista I thought my problems were over. I downloaded the newest version of itunes and imported a fraction of my music collection to test it. Still no luck as it still will not find the files. All my music files come from many different sources and this happens to random files from each source including the store. In one case it even deleted a file for an audio book when I tried to relabel it as an audio book rather than a music file.
Is there anything that I can do to the files or to itunes to make it recognize them? Should I convert files into AAC? Is there a setting I've missed that is undermining me? Please help me because this is driving me nuts!
Thank you for any help you might be able to give! ^_^

Answer 1

Using TweakUI to Move or Create Your Library/My Music Location
Use TweakUI (See: ’Disk is locked’ or ‘iTunes folder cannot be found’ when installing or opening iTunes ) to create a 'My Music' folder in a spot where you desire. iTunes should then find this location and deposit its Library files there, and the 'iTunes' folder and sub-folders as well (if you direct it to).
First, see this Article for some background information: What are the iTunes Library files?
If you cannot see the ‘My Music’ folder within the TweakUI drop-down selection, proceed on to the following:
1 On the start menu go to ‘Run’
2 Type in RegEdit
3 Navigate in RegEdit to HKEYCURRENTUSER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
4 Delete any entry for ‘My Music’
5 Navigate up the tree to HKEYCURRENTUSER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
6 Make sure there is an entry for ‘My Music’ and is pointing to C:\Documents and Settings\[username]\My Documents\My Music (you can edit the value by double clicking it)
7 Close RegEdit
8 Reboot
iTunes &/or TweakUI should now be able to find the folder.