Problems with colour scrambling with ATI Radeon HD3850

Out of nowhere, playing 2 games specifically (Warcraft 3 and Neverwinter Nights 2), I get a lot of strange colour scrambling.

In WC3, the screen flashes a lot and I get some green vertical lines. In NWN2, I get flashing white and green squares.

I have updated my video card drivers to the June 2, 2008 driver. I just installed SP3, but the problem still happens. When I run 3DMARK06, it gets through the whole test no problem, but messes up midway through the first test for about 45 seconds (i see a lot of flashing boxes, green lines everywhere), and then it fixes itself).

I do not see this problem with ANY other game (including TF2), nor do I see this issue doing anything else on my computer.

Anyone have any ideas?

I'm running XP Pro SP3
Intel core2duo E6750 @ 2.66
2gigs corsair DDR2 ram
Mobo: Gigabyte P35-DS3L
DX: 9.0c
Any other information required and I can provide it.

Thanks in advance!

sounds a bit like artifacting from over heating.

Is it overclocked? is it after a LONG session?
Have you checked what Temp your GPU is running at?

well my problem is i play world of warctraft too and what it is that my screen will black out and i wud have to alt tab for the screen to reappear and also it wud freeze up on me and i wud have to restart the game . but now its where it the words are all scrambled and the game wud freeeze the whole computer , i try everyday to get on and when i do ill move one cell in the game and itll **** up and i wud restart. my friends tell me i need a new video card and others tell me to see if anyone else has the same issue as i am