There is no video signal coming from my pc.  The monitor is showing no signal.  I have tried swapping Monitors with no effect.  This WOULD INDICATE that the graphics card has failed , but I've tried booting it up with another card (Matrox G550 dual head) with the same result.  There are no irregular bios beep codes that would indicate where the problem is.  Does anybody have any ideas before I try to swap out the motherboard???How's that power supply working? I would swap that  one out briefly with a known good unit and see what happens.

What happened prior to this event?

If power supply is found to be good - Is this a PCI card? If so, try another slot. Try that card in another machine.Power supply APPEARS to fine.  The pc sounds like its booting up.  I'll try the card in another pc.So it is an AGP card? I SUPPOSE you have tried removing and reseating the card?Yup, tried that.  The matrox card I tried was a pci one (tried it in different slots) which didn't WORK either. I'm going to try that in another pc as well just to confirm that it's working ok. Watch this space.We'll be here..........