on normal mode it freezes.
on safe mode, it tries to log in with user called user (which is mine) but i changed the password..
if i remove the password, everything goes back to normal...
I'd run a virus and malware check.
It seems odd that it's trying to auto-login without you knowing. It's perfectly possible to set auto-login (see here for Windows XP for example), but I would have thought you'd have remembered doing that.
Did the problem start at the same time you changed the password? The password is stored in the registry for auto-login to use, so you'd need to update that as well for it to continue working.