No power on start up, replaced PSU, still nothing.

[blackn1ght]

Brief
My PC won't power on what so ever. Completely dead. Replaced the PSU, thinking it was the PSU, but hasn't fixed anything. My system is 1 year old, with no previous hardware problems at all, which I built myself.

What Happened?
I had to go away for a week, so I let my girlfriend borrow my PC whilst I borrowed her PC. During this time, she powered it down fine at night, went to turn it on in the morning, but it was totally dead, the fans don't even spin up.

My diagnostics
I swapped the power cable from the monitor to check that it wasn't the fuse in the plug, but no joy. I figured considering that the fans weren't even coming alive, that it would be the PSU. Ordered a new PSU, fitted that in, tried turning it on, but still no joy, absolutely nothing. I came to the conclusion that it can now only be two things - the power switch at the front of the case or the motherboard.

I disconnected the switch from the motherboard and shorted the pins to emulate the switch being pressed, but still no power. I do have an old motherboard from my previous build that I didn't throw away, so I installed that, hoping I could use it in the mean time, which does power on with the new PSU and the original PSU. Nothing works on that old motherboard, but the HDD's and fans do spin up, so I guess that means my original PSU is fine, and that my motherboard is fried.

My System
PSU: FSP-Group FX600-GLN (600W)
CPU: Intel Q9550 w/stock fan
RAM: 4GB (2x2GB) DDR Corsair 1066mhz
MTB: Gigabyte GA-G31M-ES2L
GPU: nVidia 8800GTS 320mb
OS: Ubuntu 10.04 x64

No hardware changes since I built it a year ago (pretty much to the week), no BIOS upgrades, no OCing done. The system wasn't plugged into a surge pack.

My Question
So, my question to you is, does this sound like the motherboard is fried, or something else that I haven't thought of? Also, if the motherboard IS fried, would it have taken my CPU, RAM and possibly graphics card with it? I don't want to go through the hassle of ordering the motherboard only for it to not be the problem, and for the CPU to be fried too!

Many thanks in advance!

 

[dndhatcher]

The system wasn't plugged into a surge pack.

Its possible a surge took out anything or everything. Only way to know for sure is try them in a working PC.

 

[blackn1ght]

Well, I think I've figured out what the problem was. I rebuilt the PC after trying out my old hardware, without connecting all of the fiddly items like the front audio and USB, to take it to a shop for them to diagnose before I went and purchased some new equipment, and decided to just give it one last try for the sake of it, and, it booted up!

Afterwards, I powered it down, plugged in the front USB, tried to start it again, and nothing, dead. Undid the connections, tried it, and it booted up fine. The front USB ports aren't too important, but I still use them quite often, so I think I'll get a new case, this one is about 10 years old now anyway!