How do I either find my old roommates account on my computer or how todelete the account without losing files

Answer 1

Well that depends on the version of Windows.

If it's 2000 or XP, then look under C:\Documents and Settings. You should see a folder with his login name on it. You could wipe that entire folder out (if there's nothing there you need to keep) and not lose any of your files. You just need to have admin rights.