When you say 'turn on auto login' you mean this kind of procedure? I've done that on a few PCs and never had an issue. I can't think of what would cause it to destroy the user profile other than some ...
I've tried disabling auto logon with TweakUI, by running the command "rundll32 netplwiz.dll,ClearAutoLogon", by disabling it in "control userpasswords2", and by editting the registry. After trying any ...