No display on Onboard VGA, possible motherboard problem?

Hi

We recently encountered a few issues with 2 PC's with onboard VGA where you plug them in and no display appears on the screen. The fans are whirring away and there is power to the motherboard, there isn't any POST beeps either.

We have completely stripped the machines so the only thing connected is the PSU, to the motherboard, CPU and memory and still it doesnt work.

Which leads me to a problem with the following:

CPU or motherboard

I have tried an AGP graphics card to identify if the problem was with the onboard graphics but still no display.

This has happened on 2 identical machines which same spec in a matter of days, the other 20 machines in this suite seem to be ok. The machines are approx 3 years old.

Has anyone else suffered similar problems, is there any cure?

On the subject of motherboards and testing. Does anyone know if a product can be purchased which will allow techs to test motherboards so we have an instant answer whether the motherboard is faulty. I know there are tools you can use in BIOS or windows but that means the machine needs to be in some working order and wouldn't help if you have issues where you cannot see the display.

Any help would be most appreciated.

You could look into a post card, gives you a visual indication of the initial post sequence and where it stops.

They come in isa, pci, parallel, mini-pci and usb versions.

Ben