randomly start and shutdown

Karsten75's answer may not help, but you haven't provided any info about your system; therefore all we know is that it's broken. Provide full system specs and a better description of the issue and then we could help. I presume that "my pc is not start early it required a lot time to push power switch and also shutdown randomly" means "Initially my PC would start and I had to press the Power switch several times before it would power on; it also randomly shuts down". Providing an accurate description of the issue makes it easier to suggest a solution.