Power supply check
First, make sure that the power cord and plug are stable and not loose or damaged. Change the socket or plug it in again, maybe you can wake up your computer!
Show fitness
If you have multiple monitors, try connecting only one monitor to see if it can be turned on smoothly. Sometimes, too many monitors will make the computer "indigestion"!
Memory arrangement
Check the computer's memory to see if it is loose or damaged. Gently pull it out and plug it in, and maybe it will solve the problem.
Safe mode start
Try to start the computer in safe mode, which can help you diagnose some minor faults in the software or system.
Hardware physical examination
If all the above methods fail, there may be something wrong with the hardware. Check hard disk, video card, etc. It may need to be reconnected or replaced.
Ultimate first aid
If all the above attempts still fail, you may need to consider reinstalling the operating system or calling a professional computer doctor for help.