Question PC starts lagging and it won't shut down or restart

Mar 29, 2020
Hello, I have posted a question before but got no response. I have since tried to fix the problem but it is still there.
During use, my PC starts lagging and nothing works properly. The sound in my headphones starts sounding scratchy, my cursor is lagging when i'm moving the mouse and the PC won't restart or shut down properly, I have to restart it manually on the button for the PC to stop lagging but after some time it starts lagging again. I sent it for RMA 3 times and they said all components pass the tests. I have no idea what the problem could be. I haven't tried to re-install my OS yet. But I want to hear some opinions as to what the problem could be.