Ok...SAME problem today....but this time, I tried a lot with the 6800 GT and if it booted till the Windows XP scroll bar, then the whole screen was filled with artefacts......
Right now, using 440 MX ....seems to be working fine at 640 x 480.
I am wondering if it is a PSU issue..... coz the 440 doesnt need an external power connector....
Am going to check the voltage readings now with a DMM....