Uninstalling java shouldn't have affected your library. Had you changed the location of your saved folder? The default location is C:\Documents and Settings\"your account name"\Shared. Try searching your hdd for your files. From your desktop go to Start>Search>All Files and Folders, and search for them by title or file type(mp3).
If they did get deleted, you'll need a file recovery program to get them back. See this thread for advice:
File recovery advice!