Garbled screen in some games and apps

[digiplaya2005]

Hey, i've got this strange garbled screen when I load Tux Racer and some other games. The monitor also says "Invalid sync range" and usually I can't get out of the game without rebooting.

Anyone got the same prob or maybe have a solution?

by the way, my card is ATI Radeon 9550. (and please don't ramble on about how crappy ATI is when you reply, just got it because of price.)

thanks a million!
tom