I recently "tidied up" my computer, updating various softwares, scanning etc. I also ran the Disk Cleanup and Disk Defragmentation programmes. However after doing both of these 3 of the 4 user accounts on my computer no longer seem to be working. Mine (the one from which I ran the cleanup etc) is fine but the other 3 don't seem to recognise that they are there. Through the Control Panel it still says there enabled but when trying to logon under them some pop-up comes up and although it does eventually logon on it seems to have reverted to the setting for a new user account (or guest), not remembering anything about the accounts. Dont think the defrag caused this (all accounts worked normally before I did these two things)...but perhaps I "cleaned up" something I shouldn't have! Is there anyway I can find out what's going on / restore it? Of course I could probably delete/recreate the accounts but would have thought id lose all bookmarks etc and importantly 3 itunes libraries! Any help is much appreciated. Hope i've explained this adequately enough.