"No Signal" on monitor when plugged into GeForce 7100 / NForce 630i!!!

[Sympto]

First off, let me say I know nothing about computer hardware so it'd be great if any reply can be put in simple terms where possible.

Ok onto the problem...
I just recieved my computer back from the place I bought it (only about 10 weeks ago), the graphics card was playing up and the computer was shutting itself down. They assured me they'd fixed the problem and installed a new graphics card. I got it home, set it all up and when I plugged the monitor into the port "No signal" popped up. I then tried the on board card and it worked fine. I reinstalled the new cards drivers, still nothing. Is it a faulty graphics card? Is there something I can do without removing it (I'm under warranty) to fix it.

 

[john_marcuscaps]

Try re installing your graphics card physically maybe reseating fixes the prob.
uninstall first the nvidia drivers and turn off pc.

remove the video crd and try to spot dirt on the interface and blow em out if there are any. put them back and see