At Christmas (When my computer was new) I had no problem switching users with the fast user switch. But now, if i'm logged on to one account, and i log into another, and try to switch back to the original (after pressing WIN+L to get to welcome screen) it will SOMETIMES (not all the time, but about 75% of the time) give me a long message, that says something like, "Windows cannot switch accounts, blah blah blah, you may have to restart". Restarting never solves the problem. I just have to keep clicking on my username and eventually it will work, although as far as i can tell it's just random. The only thing i can remember changing with the log in stuff was the welcome screen background with Style XP. But I don't think it caused problems. Any ideas?