When playing games it always lags..

[tbhcam]

Hi, I bought this computer about a year ago today. It was on a website that you can customize your own computer. I bought it, it started to run great, then over the year, more noticeably about 4 months ago it started to run slow already. Then these last few months have been irritating for me. The games I mainly play are Overwatch, Rocket League, GTA, Heroes of the Storm, Player Unknown's: Battlegrounds.
My question is: Why would it be running slow? Could it be the monitor i'm using? It's at least about 10 years old. I also have reset my computer fully but it hasn't fixed the problem.
Overwatch runs at about 50fps on low. PUBG probably runs at around 40. HOTS and GTA not sure.

System Specs:
-Graphics Card - EVGA GTX 960 ACX 2.0 2GB
-Processor: AMD FM1 Processor - AMD A10-7700K 3.5GHz (Quad Core) W/ R7 Graphics
-Operating System - Windows 10 64 Bit
-Power Supply - Standard 500 Watt
-MD FM1 Motherboard - Gigabyte GA-F2A88XM-D3H

Thank you!

 

[JackTheGamingComputerNoob]

I am by no means good with computer hardware but I know my way around software fairly well and if you have completely factory reset your computer then it is probably not a software issue, again I am no expert but a factory reset should have fixed the problem if there was any thing slowing your computer down like viruses or just unnecessary programs running in the background.

Have you recently upgraded to a different operating system?

Have you updated all you drivers?

Have you ran a hardware monitor to check what temperature you are getting up to inside and outside of games?

You should also open up task manager and check how much ram and cpu is being used when outside of games.
If you have done all of this and are sure that its not a software issue or something slowing your pc down then I could only assume that it is a hardware issue but like I said before I am very inexperienced with diagnosing hardware problems so I can't help you there.