Bad Power Supply ?

I know this may not be the case, but creafully check ALL the USB connectors. I've seen damaged/shorted usb ports give the EXACT symptoms you describe

dr format

I have seen this a few time with almost exclusively Dells. Just for fun, unplug the power cord from the U.P.S. or surge supp. and examine the three contacts. one should be rounded, and two shaped like a blade. touch all three to a convenient metal surface, thereby shorting the three of them together. Again, do this only after the power cord is unplugged from the power source. This drains the capacitors inside and usually allows a boot or two afterwards. Might be worth a shot, and will tell you if the power supply is bad or not.

What do the diagnostics LEDs tell you Farrar?

http://support.dell.com/support/edoc...n/advtshoo.htm