Jeff, I have this same problem with a Gateway I have. Drove me nuts for a long time. Turned out to be somthing with the monitor / video card connetion. If I remove the monitor connector from the PC it starts right up. Then I connect the cable and it keeps working until the next time the power strip shuts off for whatever reason. Why , I don't know , but it works everytime. Go figure! Not saying this is your problem but it may be worth a shot.

have only the video card in the system along with the RAM,hard drive and then reboot the system.. if the system boots then there is a problem with the other cards otherwise its the motherboard.. check for the diags light behind the system box

cheers

i dont think its the mother board i think its the processor fan for sure.. just check it again..

i doubt if its the power supply as well

cheers

Dell is sending a new power supply, but in the meantime we took it to a local guy who tried a generic power supply.  He said it only makes a high pitch sound, and unless the Dell brand p.s. is radically different it could be the motherboard.  Has anyone ever heard this scenario before?