Windows 7: users change problem

hi
Maby somebody can solve this problem:
7 users in one pc
I logof from one user, and when i logon the
other, screen comes to be dark
Nothig helps except restart button.
It happends not every logof / lofon and
not on permanent user
many thankes for your help
Amir

See if anything in this tutorial will get you going again. It's similar but not ter same as your problem but it might do it.

User Profile Service failed the logon. User profile cannot be loaded.

Thankes for your answer
But now i saw i get "out of range" massege when it happends.
Should i increase monitor's refresh rate or decrease it?