I have Win 7 Ultimate and have 3 user accounts, say A (an admin), B (a standard) and C (a standard). I don't seem to notice any problems logging in into user A and B.
However, I noticed that when my daughter tried to log in into her account (i.e user C), she sometimes got a dark blank screen. As far as I remembered, it had happened like twice or three times. I had to do Cnt-Alt-Del, and then chose "log off". Then I tried logging in again and it would normally work.
Yesterday, it happened again, and when I tried to logging in (I tried it twice), it didn't work. So I finally have to restart the PC and then it worked.
I am not sure what the problem is. I would appreciate any help.