To fix the corruption you just need to rebuild the library
WMP11 on Vista, please make sure you have this update - this will make your library more reliable. Then: the library is per user and can be found at
http://support.microsoft.com/kb/941651/en-us "%LOCALAPPDATA%\Microsoft". Shut down IE, Media Center, WMP, and anything else running (such as the Windows Media Player Network Sharing Service, which you can stop in the Administrative Tools:Services control panel). Then rename the "Media Player" folder there. At that point WMP should work correctly again.
http://zachd.com/pss/pss.html#medialibrary