That slow scan can be a clue.
First, take Grif's advice and let's see what RKIL finds. Just that and in about a minute we'll see if something else is up.
Remember that even if we eradicate all pests, that's not going to repair a dinged up OS. And OS repair is more than files so be sure you are preparing for the final solution.
But the slow scan has been a sign of heat or failing HDD. I don't see much PC detail so I'll wait for the RKILL result.