2 yr old Homebuilt, Can not turn it off

[fl_dolphin]

I built this system about 2 years ago

MOBO is MSI 7030
Video Card is Gainward 5900 XT
3 Hard Drives all connected SATA

The D-Link has Three red Lights top 2 and bottom left are red, bottom right is off.
The computer will not shut off unless I turn of the main switch on the back or unplug it.
It will not post ne beeps. The monitor "On Lite" just blinks, I connected the monitor to my laptop and it's good.
I have checked the connectors from the front panel switch to the "PWSW" header on the MOBO and the computer stays on if It's pluged to the mobo or not. I have shorted out the "PWSW" connector on the mobo it makes no difference.
the system just runs untill I turn it off on the back or unplug it.

This all started about 2 months ago, to get the computer to turn on I had to turn the main power switch on and of off to get the computer to boot. Then the front panel switch would not turn off the computer. Now when I turn on the main switch all the fans run the light come on the HDD spin up. I thought it might be my video card and switched it out with another. Same thing
No Video - Monitor Light Blinks- All Fans Spin - HDD's Spin up. Everything sounds and looks good. But no Boot.

 

[fl_dolphin]

Common ppl, there has got to be some one smarter than me in the last 13 views. Help me out here plz

TIA

 

[agissi]

Sorry I have no idea but heres a free bump for help

Welcome to Techspot.

 

[halo71]

I am not 100% percent sure, but your symptoms are similiar to ones I had once when a PSU was failing.

BTW....WELCOME to Techspot!!!

 

[Tmagic650]

Yes, replace the power supply

 

[fl_dolphin]

Thanks for the help guys, I was thinking the power supply was good cuz everything was running,
I found this pin out link and checked all the Voltages.
http://pinouts.ru/Power/atxpower_pinout.shtml

all of them check out correctly. (I have some electronics background). The one that stumped me is pin 14 (/PSON)Power Supply On (active low). It shows a direct short to ground (low) and if I pull of the "PWSW" connecter it should go high and shut the computer down. It made no change, on the multimeter or on the computer. BTW Pin 8 PWR_OK is at +5v DC.

I ahve another power supply but it's only 380 Watt the one in the computer is a 420 Watt Raidmax. If you really think it will help I will swap the units. I just belive I will be creating more probs by pulling it out and putting in another if this one checks out good.
Plz let me know.

TIA

 

[Tedster]

It's worth changing out. Once they fail they could take out other components. Replace it while the rest of your system is ok.

 

[GRunyon]

Reseat all the connections from your power supply to your motherboard and other components before you spend money. There could be a faulty connection between the power supply and the power button. Happened to me once. True story.