Screen break up - G400

[tycho]

I run a G400 32Mb single head card and I think I have an intermittent hardaware problem. (Win 98se, Abit BX2, O/C 112MHz (not 100MHz))
Lines on the screen shift and break up the image (this happens once a week but seems random)The cursor turns to a black square (2cm x 2cm) and the icons are corrupted and are nolonger 'live'. I have to hard reboot and it may not recure for another week. It isn't a virus, I have the latest drivers 6.04 and it happens with these and the previous drivers.
Has anybody met this one before?

Thanks Paul

[ayoub_ibrahim]

tycho,what speed is your AGP running at?

[tycho]

Thanks for the replies. I operate the G400 at 2/3 bus speed - 75MHz. Temperature of the CPU (case) rarely exceeds 40 degrees C. If it is temperature related why is it OK as soon as I reset? I will check the seating of the heatsink though.

Thanks Paul