It's hot recently, so the computer will start flashing after playing for a while.

This problem is very simple. The video card or CPU is overheated. This situation is mostly caused by you playing large-scale games or running large-scale software, and the heat dissipation effect of your computer is not very good. It is suggested to clean up the dust of the fan to make it dissipate heat faster, see if there is dust near the video card, and scrub the video card with alcohol. I think a better fan will solve this problem.