How do i reformat?

U l t i

Commendable
Jul 18, 2016
13
0
1,520
So i posted a thread saying that my pc isnt performing like it used to, my fps being really bad and spiking low. A few said to reformat. But all i did was do a clean install of windows thinking any viruses would be gone. I dont remember reformating anything. How would i do so?