Question My pc games are all of a sudden running slow and I have no idea why

Jul 23, 2020
I recently got my pc at Christmas last year it was a prebuilt one off amazon
When i first got the pc it was running games fine with decent graphics settings aswell i could run pretty much any game with around 180 fps. About a month ago I got a new game for my xbox and played that game for a few weeks without hardly going on my pc. The only times I would go on my pc was when I was doing school work. I recently started playing it again and my games have really bad fps and can become unplayable at times. Even on the lowest graphic settings. Games that were fine before such as fortnite, subnautica, gta and many more are really bad to play now. I've read a lot of things on forums and tried a few things to try fix and nothing is working if anyone could help i would appreciate it loads as playing games on my pc are just not fun anymore.
My specs are
GPU- Nvidia geforce GTX 1050 ti 4g
CPU- AMD FX 8300
RAM- 16G
MOTHERBOARD- m5a78l m lx3