stange graphics card... problem?

when i tab out of counter-strike on steam a weird red line stays along my desktop, it goes away when something like an icon goes over it, it's ver multicolored, but mostly red with some specks of white and green and other colors can be seen, it's a very very thin line that goes straight across the desktop, I'll get a screenshot next time, but for now if you know any help is appreciated

 

heh , heres a no brianer: don't alt tab out of cs.http://forums.majorgeeks.com/images/smilies/tongue.gif