Query "damaged" video card - see if you agree

Hey guys.
I recently purchased a gigabyte 8knxp motherboard. It was running fine for about 2 months with my old gf4ti4200 leadtech vivo.
All of a sudden I got a bluescreen error on startup (as soon as windows xp logo apeared) and a stop error of 0x00000024 ntfs.sys.
Thinking it was the harddrives I rebooted a few times after failing to get recovery consol to work, and the problem got worse. Now i was getting NO DISPLAY on my monitor. Not even a ram count of the video card.
So I took it back to the shop and watched the techy fiddle.

Heres what I saw.
1.When my gf4 was replaced with an alternate gfx card we still got NO DISPLAY
2. When either my gf4 or the replacement card was yanked hard in and out (bending the mobo) the display suddenly appeared. But it would get to XP log in and bluescreen crash to 00x0024 stop ntfs.sys
3. Admittedly my gf4 seemed to work less often than the replacement card when yanked back and forth, but it still worked.

Now to me all these problems point to one common component. The motherboard.
However the techy for some reason thought it might be my video card (which is the only component I didnt by from them) And said that faulty currents in the video card may of damaged the MOBO.

I got a new mobo (which is working) on warrenty. But Im kind of scared of putting the so called "faulty" gf4 in it. So Im testing the gf4 on my second (crapy) computer now, and its working fine.

Finaly, the question. Whats your oppinion? do you think the techy could be right? Is there any way of finding out if my vid card is faulty. Even though its working perfectly in my second computer?

Thanks and sorry for a long winded story
Frenz