I would say that you are facing a hardware issue. Most probably your laptop is overheating and needs to lower the temperature before turning back on. Could you check PC temperature the next time you are able to boot? If the cooling fans are not running as expected, the temperature may get high quickly.
The problem is that if you are facing overheating, the PC should turn itself off when temperature gets really high. So, if it is not overheating there may be a power button issue or a motherboard problem. In order to investigate the issue further, you may need to seek help from a technician.
Hope this helps