atikmpag.sys booting BSOD

I would try everything. Just use it as normal and the things that caused your problems, do them much more often.

What card are you going to be using? Also show the same screenshot of GPUz that you did before.

Hey, essenbe, sorry for the lack of replies (had some personal stuff to do).

I had some weird issue with my wi-fi USB, so I decided to try installing a wireless pci card (CN-WF511) to see if it'll fix it, but then the pc wouldn't boot at all. After removing the pci card, the pc is now able to boot. Unfortunately the BSOD issue came back again, but I guess it's better to go to safe mode, restart and then log in to Windows rather than having unbootable pc.

As far as the GPU goes, I found an old nvidia 8800 GT. However, this (now fixed) unbootable situation doesn't make me really happy ... swapping the amd for the nvidia shouldn't be a problem (it has been used on it before) but.. not sure if it'll boot again. Tbh, I'm sick of those problems (lesson learnt, never ever buy 2nd hand GPU) and I'm going to build myself a new PC "from scratch" in 2-3 months.

Would you still like me to try the nvidia? Or closing the thread is a better thing to do?

Edit: My BIOS Version/Date is Award Software International, Inc. F2, 4.1.2008. According to the official gigabyte page, there're quite a few updates. Perhaps updating the BIOS could help?

Yes, updating BIOS could help. Try the Nvidia card. First, download the Nvidia drivers for the NVidia card. Then, with the AMD card still installed, uninstall the drivers, reboot and run DDU selecting only ATI drivers as stated in this tutorial. Drivers - Clean Left over Files after Uninstalling The only exception is instead of restarting, shut down. Swap the cards and install the NVidia drivers, using this tutorial. Only install the Graphics driver and PhysX.
NVIDIA Drivers - Avoid Problems

You are at least running X16 instead of X2 like you were before. That may help you out. I know you will get better performance.

Possibly. It looks that way unless it wasn't seated correctly.

Read the descriptions of the bios update. They usually tell what the update does. But, I am inclined to say it is the card unless you want to re seat it and see if it runs correctly. But, if you try that you need to get rid of all Nvidia drivers before you make the switch, then install AMD drivers for that card. If it still says X2, you need to reverse the process.