I have a 300watts ps and a 128mb radeon 9800pro ati orignal from many weeks and months now.
Sometimes now it the computer shows colours,
the boot screen of win xp and win 98 changed colour ,pink or purple for a few seconds and got ok again.
Changing colours has happened earlier.
Also,when i install omega after a few days the games start showing artifacts.
The issue could bea as simple as a frayed cable between the monitor and the PC…Used to see this problem often on campus PCs…just try to twiddle the monitor wire if and when this issue occurs again