AcBel is listed, but it does not appear to have been reviewed by a trusted reviewer. As such, I look at that negatively, as any company that was proud of their power supplies would have sent out units to lots of sites that review power supplies to get them known to the public. And it appears that AcBel has not bothered to do that.
What you describe could be caused by the CPU overheating to the point where it powers down to protect itself from heat damage. Or the motherboard could be defective. Or the CPU cooler might have been installed improperly. Or the power supply has an problem.
Did you build this computer yourself?
Did you make any changes shortly before this rebooting started?