iMac boots to white screen, fan gets very loud
Hello everyone. I have an iMac that was giving me the issue of just booting to a white screen, and I could not access boot menu, recovery mode, safe mode or anything else, just white screen. After extensive searching on the internet and changing RAM and reseting PRAM, I came to the conclusion that the GPU card was faulty. I have successfully replaced the card on a different unit so I decided to buy one from a reputable seller on eBay and replace it on this unit. Long story short, after replacement, the same issue was happening: booting to a white screen and nothing else. I thought that maybe I had received a defective GPU, so I sent that one back and bought a different one. I am now at a loss after the second GPU replacement: the same issue is there, which is booting to a white screen, except this time the fans get very loud and fast after a min of being on. I would appreciate any and all help with this issue! Thank you.