Good day,
I have a tricky problem with my computer, and would appreciate some help.

Now what it does is the following,
As soon as I start my pc, it does the tests checkups and all that jazz,  but when it gets to my windows7 ULTIMATE startup, before the login page, my pc switches itself off, note, it does not restart.
I thought that it might be windows7 so I backed up my files onto my other hdd, and reinstalled windows7 ultimate. And at random points, my pc just switches off again.
next i took out my recently installed ram, and left the old ram in, and it did the same, tried that same thing with leaving in the new ram, and taking out the old ram, still the same problem.
Next, i swopped my power supply with another ONE i have, same thing.
tried another hdd i have, same deal.
thought it may be a cooling issue like i had with  previous pc, installed a cooler master  jet, same problem but my pc now runs on 20 degrees and my mobo on 30.
I checked my pc for burn marks, no burn marks.
checked my cpu, none either,
I changed my bios to the fail safe settings, and it still does the same,
to rule out the disc i tried installing windows 7 ultimate from a friend's disc, still the same,
to rule out windows 7 all in all, i tried installing xp, still the same.
ok,
so,
my stats ae the following,
AMD K8 dual core,
nvidia geforce 6100 pm-m2 v2.0 mobo
4gb ddr 2 (800) ram,
Seagate 500gb 7200rpm,
samsung 160gb 7200 rpm,
nvidia px8400gs tdx
600watt BAOBAB psu newly installed,
and a standard dvd rw sony

any help would be appreciatedThats an ECS MBoard.....it's either the board or the PSU.

Borrow a known working PSU of the same or greater wattage and swap it in there to see if it's the culprit.
If it is i'd invest a bit more in the next one as it's an important component.Actually I replaced my psu with another one, a gigabyte of equivalent size and wattage, still doing the same.
Its doing the same no matter what os I TRY, busy formatting again not the quick format the proper one. Then i'm afraid it's the MBoard.Is it Repairable?

I saw on another forum the same problem, same pc funny enough, and they SAID it could be a capacitor, and i checked all mine and they are fine.
Ok i got xp to run to the desktop after installation, and it did the same nowI would take it to a local PC shop to have them confirm it's the MBoard...alright i build pc's, and such and a friend of mine also advised me to flush the bios and get an update, currently sitting with my laptop. waiting on a solution to this, my friend the IT tech also said the mobo looks fine, settings are fine,
no clue what to do now
oh it started about two or so days ago, and the more i started it the worse it got, it wont even read from my 500gb now, only the 160 thought that might be usefull to know
oh and also has not gone off for a while now that i am running it in safe modeWhen you re-installed did you also remember to re-install all drivers starting with the MBoard chipset drivers ? ?

Not sure how he can just look at a MBoard and determine it's OK...

P.S. If it ran before this started i seriously doubt it's a BIOS issue...