Weird graphics issue

A couple of months ago, my screen suddenly turned black during a game. I tried rebooting and managed to boot in a funky VGA-mode. I was only able to use 640x480, anything above that and the screen started acting weird. The display would start blinking and then completely black as I tried the higher resolutions.

I tried to solve the problem by reinstalling drivers and installing a fresh Windows and Linux, without solving the problem.

I sent my graphics card in for repairs, but it apparantly worked just fine.
I tried switching monitors to an identical model, without solving it.
I installed a new motherboard, without solving it.
I put in a bigger PSU, without solving it.

Now... when I unplug two of my three harddrives and my DVD burner, I'm able to use 1680 x 1050, with some blinking, but it's still better than before.

What could be wrong? Did my computer all of a sudden decide to use more power?

Intel Core2 Duo 2,4GHz
Asus P5Q
GeForce 8800GTS
Samsung Syncmaster 205BW
550W PSU

YARR!

I agree, check adaptors and/or connectors in your case and to your monitor. Switch components around if you can or ask a friend to help you by asking for replacements or exchanging components (risky for your friend, though).

Esop!