Shuts down during start up

Hello, I have a E-Machine T3626 that shuts down after the splash page. (Will stay on in CMOS)
I have tried multiple OS on this machine, 2 differnet versions of Linux, 1 bootable on CD.
It shuts down somewhere before a full boot while testing hardware. (Unfortunately no matter how many times I try and read the last line I never get it.)
Windows XP - gets to "improper shut down select Safe or Last known good configuation" then shuts down after that.
I have done everything but change out Motherboard, waiting for you to confirm it is that.
I have disconected Keyboard, Mouse, Monitor, Floppy, CD-ROM, USB Cables, Media-Card Cables, Hard-Drive, RAM, Cooling Fan, PCI Cards.
I switched out the Power Supply for equivilant
Did not try replacing Mother Board Battery. Can I simply switch with nearby computer? What harm will this process do to nearby computer?

 

If you have removed everything but the motherboard then it is very likely that that is the problem. The motherboard battery will not help in this case as far as I can see.

 

I verified that batteries are the same. I left out of computer for 1 minute. Reset time in BIOS then tested. Still experiencing problems. So you were right.
Are there any steps that I can take to make 100% sure before I spend $150 on a new MB.

 

None that I can think of, you have ruled out other causes so I would go ahead and replace it.

 

Last chance to solve...if it helps it shuts down 23 seconds into boot. I never get the POST beep. (Should beep because I get beeps when RAM is removed)

 

Well then POST is not being completed. You might want to try to flash the BIOS.

 

Sorry to keep dragging this out. How do I flash BIOS? My research shows I have to download from Motherboard manufacturer who is ECS. I have submitted via their form for a response since my MB Version MCP61SM-GM v: 1.0 is not even on their site. Is this something that I can get just simply knowing I have Pheonix Award v 6.00PG?

 

Have you tried tracing the motherboard on the ECS site by using the options on the left hand side of their site?

To flash a BIOS you need a floppy drive or other bootable media, and an actual BIOS file from the manufacturer.

 

Sorry for delay, I posted yesterday but it must not have done it 100%.
Anyway, I tried to use their side menus and my motherboard is not listed. I also tried doing a search and that still does not bring it up. I have located on a NON official E-Machine fourm a BIOS Flash utility but unfortunately no instructions.
Can is get this on a USB and put in broken machine. I can't screw up my Vista labtop.