Low FPS in basically every game - need help!

So i just recently got my new computer, well I got the parts to it and put it together. Everything went fine and was working fine until a few days ago. (Computers about a week old at this point) The first few days I spent downloading games and drivers and all the games I played ran wonderfully. I was running CS:GO at 220 fps and higher, and all other games were a walk in the park for my computer. One random day I just turned on my computer and went to play CS:GO and I was stuck around 50-60 FPS, and have been there ever since. (This happened a few days ago, about 3 days to be exact) I tried updating my GPU driver, there was an update which updated, no change. I ran a full computer scan to see if any viruses were dragging my performance down, no change. My computer is also running at low FPS for all other games. For example, I was running Far Cry 4 and it was so laggy it was basically unplayable, and i'm very tolerant when playing with low-fps. Far Cry 4 should be running much smoother from what my Graphics Card has it optimized at, yet it is not at that performance at all.

Build:
CPU - i5-4690 @ 3.50 GHz
GPU - MSI Geforce GTX 970
Motherboard - Gigabyte GA-H97-GAMING 3 ATX LGA1150
RAM - G.Skill Ripjaws Series 8GB

Any ideas on how I could get my performance to what it should be at because my computer should be running these games with ease. Any response is appreciated, thanks.

EDIT: I found a problem that might be it, but I don't know how to fix it. When going into the directx diagnostic tool I found that my display had the intel hd graphics instead of my graphics card. How do i change this?