Can anyone help me?

Hello! I installed a version of Windows 10 Ghost spectre super lite without defending it and my computer is constantly using 100% CPU, in addition it is having a lot of problems running games, games usually start normally (30-60 fps), but after a few minutes the fps drops to 5 and continues at 5, having to restart the game for this to be resolved! Maybe it's not an OS issue, but I was wondering if anyone can help me with that. Thank you very much