Had the same issue with an Asus Rog Strix gl702vsk, all stock. I was stuck in a boot loop and managed to break into safe mode with networking, ran a virus removal tool, came back clean. The laptop ran great, there was no stuttering or anything, I cleaned up the storage thinking it was just full, wrong. I had just over 300gb left on the hdd. I tried to boot up normally and after that, I couldn't even get it to boot into safe mode again after trying to boot normally. I also noticed the hdd was making a loud, buzzy, grindy kind of noise. Was I wrong to replace the hdd? (I had a spare I had kept safe out of another pc, 500gb) I also have another question. I was weighing the options to go back with a solid state drive that fits in the sata port. Would anyone recommend this? Where would I get one for the best price? I was also thinking of doing a pcie ssd as well.???? (correct and educate me I have enough knowledge to get myself into trouble but not enough to do things right.)