XPS 420 will not boot, fans on high

by was6477 - 1/18/10 6:16 PM

I tried to power on the computer the other day and it would not boot. THe power button on the front of the case is blue, indicator lights 1, 3, and 4 stay on. The hard drive indicator is solid for about 5 seconds then turns off. The fans remain on high. Sometimes if I am lucky the monitor will turn on, but then will shut off. I have recently switched out mother boards to a refurbished Dell, switched out the memory and have disconnected and reconnected everything in the case. Please advise. Desperation is starting....

Thanks