[SOLVED] Dell Precision 390 not booting!

I have had a dell precision 390 for a couple years now. I was in a hurry to leave, and needed my flash drive, so I just unplugged it. The computer shutdown just as it happened and I thought it was just a coincidence. When I returned home, the computer would not turn on. I thought it was weird, so I tried another outlet In my home. Still, no luck. I checked inside the computer, saw the light on the motherboard indicating power(so i am guessing it isn't a dead PSU), and was stumped. I checked all of the connections, disconnected everything inside(GPU, CD drives, PCI cards, power connectors, hard drives, etc.) and even tried booting with minimal setup. No luck. Any help would be great! Thanks.


My PC:

Dell Precision 390

-Graphics: Nvidia Quadro 295 nvs
-PSU: Standard for 390
-Motherboard: Standard for 390
-HDD: Seagate 160 GB