The screen stucks after switching users

[simonidel]

Hello,
I use windows 7 ultimate x64 for a long time.
suddenly, after i switch user, screen stucks .This is the screen that it stucks in (for example):

If I change user after a shirt time it doesnt happen, but if I switch after a long use ,it stucks.

What is the reason?How Can i fix it?

Thanks.

 

[ThrashZone]

Hi and welcome to SevenForums,
No telling why the screen sticks
That isn't the default log on screen so just how many other tweaks have you used to alter the machine ?

 

[simonidel]

What do you mean?

 

[ThrashZone]

Hi,
In other words did you use a similar process like this,
http://www.sevenforums.com/tutorials/5382-log-screen-change.html

If so which one if not the above utility to change the login background ?

 

[simonidel]

I have
Default Log On

 

[ThrashZone]

Try this 3 times in a row booting between runs
http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html