After having watched the video, I'm pretty sure you have some sort of keylogger. If it was a hardware problem it wouldn't keep dumping that text, it wouldn't be in your clipboard after having rebooted the machine. Was one of the virus scans you ran malwarebytes? If not, run malwarebytes, it's the best and always catches shit the others miss. It could be that it's not something a virus scanner will pick up, in which case you'd have to look through your running services searching for it. I could help you with that if you're willing to give me remote access. PM me for more details.