Computer will not start

[Captain Kevlar]

I have an old 2006 Acer that will not start. It's as if the power button will not start. This started about a year ago and I tried as hard as I could to start it, to no avail. Now I decided to try again, as I have no money at this moment for a new computer, again with little success. This is what happened:

I plugged the computer in and opened up the side. I plugged a mouse into the back and the laser turned on. I plugged a USB into both front and back, same thing. Still the power button would not turn it on. Using a cigar shaped voltage detector (50 - 1000V) I checked the power cord all the way to the PSU, the whole time the detector flashing and screaming. When I checked at the cluster of cords coming from the PSU's other side there was nothing. As I checked multiple things, still nothing. Until I began to pull the detector out, at which point it started shrilling and flashing while in no close proximity to anything, but still inside the case. I pressed the power button and it started up. When I plugged my monitor in it got a "No Signal" message. I fiddled with the cords before resigning myself to holding the power button and most of the LED lights at the front of the case turned off, save the large "Acer" one. I put the detector back inside the case and got no sirens. When I pressed it against the frame of the case, however, I did. I assumed the motherboard was shorting to the frame so I unplugged the PSU for a second to cut power to the front LED and started pulling out the motherboard. Even with it just laying on my desk and plugged to the bpower supply I couldn't start it through shorting or plugging in the power button, even after reseating and testing each piece of RAM.

Sorry for the word-wall, but might anybody with more technological knowledge than me know what the problem is? To me it seems like the PSU, which is something I've never troubleshot before.

 

[Outlander_04]

can you take the psu from the case , plug it in and check the output voltages ?

Id suspect its dead

 

[Captain Kevlar]

The PSU's already on my desk along with my motherboard and front panel, and there is definitely voltage now coming through all the cords, right down to the mobo. The power also goes all the way from mobo to power button.

I managed to start it again, too, once again without signal to monitor and without any lights on the panel. One thing I forgot to mention is that when I manage to get this thing turned on the fans turn on. It appears (to me) the PSU is pushing through just enough juice to occasionally star powering up, but only gets so far before it stops doing so. It can run the fans indefinitely, so the power can't be fluctuating much. I'm almost concerned it's not the PSU at all and maybe the CPU, but that doesn't wholly add up.

Is it possible that something's loose inside the PSU? I've never torn one apart, but if I have to I will. It's obviously not entirely dead.

 

[Outlander_04]

try disconnecting the front panel connectors and seeing if it will boot when you briefly touch the two pins on the mb for the power button with the tip of a screwdriver

 

[Captain Kevlar]

I've done so many times. Did so again. Didn't work.

There is something interesting though. I've left the components set up and plugged in on my desk all night and everything is cold except for what appears to be the northbridge heatsink. I know the northbridge connects to CPU and VGA, but not much else about it. Could it be causing my problems? Or is this heat normal with a shut off computer, and I've just never noticed?