Re: How screwed is my PC?
If it boots up and the HD light flickers as usual then the CPU and HD are probably fine. The only thing left would be the video card. RAM problems will blue screen you. Did you remove your video card when you tried the onboard video? If not, the comp will still try to send the signal to the vga card because the onboard video is probably disabled in your bios.
A lot of the times with VGA issues you will get a beep when you turn the comp on and there will be no screen. But that doesn't always happen.