Kaleidoscope/Distorted display

The only way I can think of to describe the problem I am having is, when i first start up, my display show's what it's supposed to but looks like a weak TV signal with white lines of 'static' going across the screen until after the POST screen. Then it gets fun. About 90% of the screen turns into blocks of different colors with text flashing in them (anything from french characters to smiley faces)

Stats:
GPU: Nvidia 9800 GX2
CPU: Intel e8400
RAM: 4x2GB OCZ Reaper 1066
Mobo: EVGA 780i SLI

I have tried updating the video driver, resetting and updating the BIOS, removing and re-inserting the video card (dusting everything while I was at it), and stripping it down to the barebones (CPU, GPU, 1 stick of RAM in the primary slot, and only the monitor and keyboard plugged in). I also tried a different monitor with the same results.

So I'm starting to wonder if this means either my GPU or mobo has gone on me. Ideas, comments, questions? I greatly appreciate any feedback since google appears to have failed me on this one. Thanks ahead of time!

If your card is a single PCB version, it may be worth reseating the HSF.

It sounds like the VRAM has/is overheating, have you tried squeezing the card(s) together?

There was a poster a while back who reported that their 9800x2 'came away' from it's heatsink after a while but if it was physically held between the hands and then pressed back together it was OK for a bit.

If the card is no longer under warranty and you are feeling adventurous you could try removing the cards from the heatsink and redoing the thermal paste but if the VRAM is fried then the problem will persist. Try to get the card tested in another machine and/or borrow a card to check that your motherboard is OK first.