A user's desktop PC shuts down suddenly every few hours.

If a desktop PC shuts down suddenly and there is a burning smell coming from the area where it is connected to the wall socket, the first step should be to check that the power cable is not damaged. A damaged power cable can cause electrical shorts or overheating, leading to sudden shutdowns and a burning smell. Inspecting the power cable for fraying, cuts, or other damage can help identify if it is the source of the problem.