Here is the problem - I handed the computer over to my co-worker, and he plugged everything in and said that nothing came up on the screen. I was hoping this was a simple problem like an unsecured connection to the monitor, but then he told me that the fans spin when he powered it on but the monitor displays no signal.
I took the computer home with me to attempt to diagnose and correct the problem. It seems likely to me that the only things that could be wrong with it are that either some connection shook loose while in transit to his house, or some component has failed after the first day of use. Perhaps the motherboard is shorting on the case somewhere, but this seems unlikely since it was working perfectly fine when it left my house.
The only time I'd seen this problem before, was when I was using an nForce motherboard and the Antec power supply was not providing sufficient +12V amps to power the system. I can't see how that's the problem this time if the power supply worked the first time I tried it! Also I connected a more capable Antec power supply last night (gives 20A on the +12V rail), but the system wouldn't boot.
I've also already tried putting in a different video card (PCI instead of PCI-E), but the same thing occurred. I even tried my AGP video card from my system in this machine (it has an unusual AGR slot for "certain compatible" AGP video cards) as a shot in the dark, but I had the same result occur. I did check the monitor on my system and it worked fine.
I tried to reset the CMOS but I'm not sure if I did it correctly for this system. It has a push button instead of a set of pins like most motherboards. I did remove the battery for a couple of minutes with the system off to try and reset it that way, but no luck with booting successfully.
I would appreciate any help that is out there. From my testing yesterday, it seems the problem is likely not the power supply, the video card, nor the monitor. The system is loosely based on the Value Gaming PC Buyer's Guide for July shown here at www.sharkextreme.com.
Here are the specs:
AMD Athlon 64 3400+ Newcastle core (Socket 754)
MSI K8N Neo3-F nForce4
Aspire Case w/ 420W Aspire PSU (+3.3V/28A, +5V/40A,+12V/18A,-12V/1.0A,-5V/1.0A,+5SB/3.0A)
Corsair ValueSelect 2x512MB DDR-400
Saphire 128MB (ATI) X300 SE, PCI-E x16
WD Caviar SE 80GB HDD (ATA-100)
Viewsonic 17" LCD
Windows XP Home