I'm not very confident with taking PCs apart as I've never built one or done any work on them before.
I've been starting up the PC with the windows 7 disc in, pressing F8 as advised but nothing is happening. It's as though the monitor isn't plugged in to the PC.
The graphics card you have only has mini HDMI or DVI. Are you using a normal HDMI lead with full size at both ends? If so, then you're undoubtedly plugged into the onboard graphics.
Edit: I see you found that out :rockon: Well done. We all have some blonde in us!