No POST, No beep, Blank Screen, Help PLEASE!

[kamikaz1_k]

hey, I realize there are plenty of threads with same problem (read them all) but i figure that getting advice for my specific situation would be better. I recently made some upgrades to my computer and after fitting up all the parts I attempted to power up. However I get a blank screen, with no beep confirming a post. The fans are spinning, and hdd are running. When i attempt to turn of the computer by holding the power button it does not turn off, only way to power off is switching off the main switch at the back of the psu.

My specs were:

P4 630 @ 3.0 GHz + Aftermarket Heatsink
GA-8I945G Pro
2 X 1GB DDR2 @ 667 + Heatsinks (*)
2 x 512 DDR2 @ 533 ( realized bad mix, thats why i take it out after)
2 x 7200 rpm WesterDigital HDD (160 GB+250 GB)
2 x 5400 rpm WesterDigital HDD 80 GB
Floppy + Multidrive (SD, compact flash, etc.) + LG CD/DVD combo drive
AcePower 520 W (12V @ 35 A)
onboard video
Monitor - VGA
80 mm + 120 mm Fans

Specs are after upgrade:

P4 630 @ 3.0 GHz + Aftermarket Heatsink
GA-8I945G Pro
2 X 1GB DDR2 @ 667 + Heatsinks (*)
2 x 7200 rpm WesterDigital HDD (160 GB+250 GB)
Floppy + Multidrive (SD, compact flash, etc.) + LG CD/DVD combo drive
PC P&C 750 Silencer (*)
BFG 8800GTS 512 OC (*)
Monitor - VGA
80 mm + 120 mm Fans

The starred items are the recent upgrades, rest of the computer is august 2004.

So far i've tried the following:
-took out hte 8800 and is tried running it on onboard gpu
-plugging everything back to my old psu
-i was thinking of doing a processor swap with a friend who has a T socket, to see if the mobo is dead. I figured i should get some more info before going drastic.

If it is my mobo, i would also love suggestions for cheap alternatives around same league as what i am trying to run. I'm going to upgrade later in the year so nothing expensive please : )

Thanks in advance for any help you can give me.

[Phaelax]

Seems odd that a motherboard would die at the same time as upgrading new hardware, so I doubt that's the issue. (although, something could have shorted while you were swapping parts).

I would put all the old stuff back in, to the point when you know the computer last worked. If that boots up ok, starting added parts 1 at a time and powering up to make sure it works. Slow, but process of elimination is sometimes the easiest method.

[kamikaz1_k]

Hey phaelax, thanks for helping out, i appreciate it.
yuh i just finished returning everything to the old configuration (to when it ran). The POST is still non existant, along with the beep and any type of screen activity whatsoever.

this can't be processor problem though would it? i mean did some heavy over clocking prior to christmas but since then i returned it to stock speed and everything was fine. I was thinking it was a motherboard problem because when i hold down the power button it doesn't turn off (only way to turn of off is main switch at psu). That is a motherboard function (right?) so i've been just looking for ways to confirm that i guess.