When ever I ';switch users'; on the computer, then log off the user I have switched to, the

with a white flashy thing in the top left corner. I have to turn the computer at the power button then. What could be wrong? A virus or something? My computer has Norton Internet security and antivirus so I don't think it's that?

When ever I ''switch users'' on the computer, then log off the user I have switched to, the screen goes blacknorton 360

You need to change Internet connections to all users..

When ever I ''switch users'' on the computer, then log off the user I have switched to, the screen goes blackphotoshop

spy ware may be the cause
I hope you not switching to another user on here....naughty naughty boy you.
If that just started happening then you may have spyware. Try these, they work and are free:

Run the tool and then download the free spyware and virus protection programs:

Malicious virus removal tool:

http://www.microsoft.com/security/malwar...

Ad-Aware Free download:

http://www.lavasoft.de/software/adaware/...

AVG Download free

http://free.grisoft.com/doc/1

Good Luck
You may have spyware!!!