Strange Cube behavior

[DMBand0026]

When my dad was on his Cube and checking his e mail, he scrolled and saw this:

http://www.davidlegatt.com/pix/Cube_Screenshot.jpg

Any reason for this happening? Corrupt graphics card? The system is a G4 Cube @ 450mhz, ATI Rage 128 Pro with 16MB of VRAM, 384MB of RAM, 80GB HDD, Mac OS X Panther 10.3.5.

Thanks for all your help. :)

Edit: Forgot to say that it happens in all apps and in all open windows, including finder, I just took a screenshot of Mall.app. And it only happens after scrolling. On opening, the windows look normal.

Edit #2: Thanks a lot to ThunderPoit for hosting :D

[alcimedes]

run the hardware test CD, see what it says. that could be bad VRAM.

[ThunderPoit]

youre welcome DMBand

[Matvei]

Graphics driver? reinstal ox to see if it helps, or drivers from ati's site.

or could be overheating. any way to check the temperature, many shareware programs do it.

good luck