Please post the Wattage of your PSU, and let us know all your PC specifications.
It sounds a lot like, once your PC uses high power consumption, it becomes too much for your Power Suply, and power off.
Of course, this is too soon to say, so please let us know before we make any decisions
😛It could also be a faulty PC part. So, please also tell me this: Does the PC crash just before it switches off? My old PC used to have a faulty motherboard, in which sometimes caused it to crash, then suddenly there was a blue BIOS flash, and just after 2 second, it would restart.
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