Vista Wont Boot~Interesting Problem

Hi, this is my first post and I've been reading and researching this problem.
I have an eMachine 2.21Ghz, nVidia nForce 405 Chipset, 1GB RAM, 400GB Harddrive, Vista Home Premium 32Bit SP2, Second HardDrive with XP SP3.
I was playing a game when I thought I heard the computer beep, but I thought, "no probably my watch". Playing World of Warcraft that is.
It just shut off. Everything but the monitor. Ever since, I haven't been able to get Vista going again. Even XP. Yeh, I was running Vista when it happened.
I've tried Safe-Boot, and every darn thing from the list when pressing F8. I've tried to restore, everything. It wouldn't boot in safe mode. I've reset the CMOS, still nothing.
I tried unplugging, pulling the battery out, and holding the power button for 30 seconds. Yeh, I tried it on the motherboard, that was the first thing I tried for resetting. I've tried booting from my Vista disc, and it will show the little graphic of the green bar showing that it's loading, then it shuts itself off.
Soon after the first SHUT-OFF that it did, it displayed only 1 error message.
- Blue Screen and something with NV___ couldn't load or corrupted(<-can't remember the rest, maybe DSP). Then it never displayed the error again.
So, I tried to give you as much information as I could with my problem. Nothing graphical will load. Thinking the nVidia integrated graphics got fried.
The only thing I can think of is to have the MB checked. I swiped out the PSU with another with the same exact specs as mine, and it still made no difference. The PSU I tried came from another working eMachine.

Thanks, in advance!!!
C.G.

I suggest starting all troubleshooting with the following diagnostic tests. They'll save you a lot of time and heartache if there is a hardware failure, and you'll have the disks on hand in case you need them in the future:

H/W Diagnostics:
Please start by running these bootable hardware diagnostics:
Memory Diagnostics (read the details at the link)
HD Diagnostic (read the details at the link)

Also, please run one of these free, independent online malware scans to ensure that your current protection hasn't been compromised: Malware (read the details at the link)

Click to expand...

If that passes, then try another video card to see if you can get a display.