If you’ve had a computer screen that shuts off and quickly turns back on at seemingly random intervals, the first place you should check is your wired connection from your System Unit to your Monitor. Ensure that your cables are set all the way in the ports.
If you have other cables, try swapping them to see if a new cable fixes the problem. If that still doesn’t work, then check your Graphics Card or GPU. Your Graphics Card may be overheating due to an accumulation of dust or it may not have enough space between other elements on the Motherboard to ventilate properly.