2 yr old computer with ssd clean os install and still runs like crap.

Hi, I got 2years old mc book pro with stock 256gb ssd in it, 16gb ram and i7 in it. It worked like charm until one day. I was just browsing online and I notice fan speed went to max and computer slowed down dramatically. It never got this slow.... so i cleaned everything i could think of and all the ram there is. Defrag the disk. Run 2 different antivirus some miner stuff found. As a lost human being I decided to do a clean install..... o formatted the hard drive. The os took 2h to install..... when it should take about 7mins. No clue please help. Is it possible I need new drive? Should I try defoulting the BIOS?