So I've had this computer for a little over a year now. It has been working fine except recently I have not been able to run games on high anymore. Now I can barely run games I used to play like Arma 3, DayZ, LoL, and CSGO. Now when playing these games I have to run it on the lowest settings and have to stick to 30 fps. I have a NVIDIA GTX 760. But when I checked to see if it was working, it showed the default graphics card that the computer came with and my usual graphics card is no where to be detected. I have also cleaned my computer and removed and put back my graphics card and cleaned it.