Motherboard faulty PCIe x16 slot?

Hi everybody on the forums, I recently tried to move my Asus Dcu2 7850 GPU to the top PCIe slot to free up some space to get better air flow but unfortunately when I rebooted my machine the resolution was back to 800x600, I couldn't crank it up back to 1920x1080, an error window would pop up (don't remember what is said though) and my games would simply not boot. So what's up with that? Is the motherboard defective or is it a driver problem (software noob speaking :/)

even if it's broken I surely won't RMA since I don't want to deal with all that stuff plus it would mean being prived of my PC for a week or two and I'd have to disassemble it which would include removing the stock 8350 heatsink who was a nightmare to put on in the first place, I was scared shitless of breaking my socket and mobo because of the pressure I had to put on it.

But still, it's good to know if something is defective just for the record. So tell me what you think about it, thank you in advance and as always, have a nice day!

Try removing and reinstalling the drivers just to see if that helps. There maybe a detection error that is causing the incorrect drivers to be used.

Just try reinstalling the drivers. Its probly the same idea with the PCIe slots as it is with USB's. Like with my xbox 360 RF board I modded so I can use my xbox 360 controller on my pc. It has to be plugged into the same usb I installed it from originally or else I need to reinstall the driver for the new USB slot. You should be fine after a refresh on the driver and a restart.