Got this classic error on an old PC, tried slmgr rearm, restarted, then when I try slmgr ato it says product not found. Also can't connect to the net, ethernet cable light doesn't even flash when plugging it in, won't find any wifi. Windows is actually legit, but no idea where the box is with the key or if that will even work. Would appreciate any ideas of how to fix this. I know I can flashdrive from scratch but there is over 1TB of shit and many professional programs installed where they only let you register it once and make you pay hundreds for a new one even if it's for your own computer. Also legacy shit where the company isn't in business and you can't register it anymore.