In answer to your question about the file names: They manage user profiles for various installed applications. Don't delete them, otherwise the associated application may not continue to work properly.
As for your second question about defrag problems, tt sounds like your hard disk is messed up. You might want to consider doing a backup of all your user files. Also, this is a good time for reformatting your drive and taking this opportunity to install a more recent Windows version.
This was first published in January 2002