How screwed am I?

So the day finally came.

My PC didn't boot upon pressing the button and I made things 10X worse in the blink of an eye, hopefully someone here can confirm my suspicions.

After pressing the button and having no boot up, I figured that perhaps it was an issue with my audio interface that was plugged into the usb socket. As I removed it, the bracket that the usb's are attached to moved and touched the case, causing a spark. I turned it off at the wall and safely removed the usb from the connection.

Press button, Life - for all of 0.8 seconds and then nothing again. The LED would flash on the power button and then turn back off by itself. It seemed to do this for a few times and then decided it wouldn't even flash the LED. I left it a while and tried again, the cycle repeated and I figured that I must have fried something and it was automatically shutting off the power button after trying too many times - Perhaps just coincidence.

I came to the conclusion that I was going to have to start removing bits and re-assemble.

I removed everything except fan connections, motherboard, PSU and CPU, then bypassed the power button and bridged the 'on' switch pins.

This allowed the computer to start up, engage the fans for 10 seconds and then auto turned off - rebooted - turned off - rebooted, etc.

I figured it was because my hard drive wasn't connected and it was in a boot loop as there was nothing to boot.


Anyway I narrowed it down to this.

Everything works absolutely fine, stellar infact - without my GPU.. (Radeon HD 7950)

If I try to reinstall the gpu, we end back up as before, with the LED flashing and nothing happening.

I managed to get my hands on a friends spare less powerful GPU (Geforce GTX 670) and fit it - PC booted up as normal, went to install drivers and the driver installation program couldn't find the GPU - It wasn't showing in my PC config either.

I decided maybe my bios was out of date and wasn't letting the new GPU self install. So I checked online and it looks like perhaps I may actually have an outdated version, so I decided to go to my motherboards bios (Gigabyte z77-ds3h), except I couldn't.

I can't remember all the different ways I tried (and nearly succeeded with) to gain access to my bios. No matter what, I just couldn't get into it. One step away each time. Every single menu either wasn't showing the enter bios option, or it would crash if I tried to.

So now what I thought may have been an easy fix (A GPU) has become a right ol' puzzle.

Have I fried my motherboards PCI slots? Is that why it won't accept the GTX?

Is my power supply nearly dead and unable to boot up my Radeon GPU (It has 2 block connectors for separate power supply)?
Would this explain why it can boot up with a far smaller GPU on the motherboard?

Or is it simply just my GPU is fried and it's stopping the pc to boot up?

I really don't want to spend money on a new gpu if its just going to be fried the second I connect her up.

Would love some ideas and thoughts here - I built this 5 years ago and it's done me well, don't want to have to buy an entire new rig ideally.

Plus I want to take advantage of black friday 8)


Cheers,