First, if it just shuts down or hangs up, it will be a hardware problem. Start by testing the RAM.
Then you can remove anything superfluous, such as USB devices, and see if that affects it.
If it's not the USB device or RAM, it could be the motherboard or CPU - new PC territory. Or perhaps, but less likely, the hard disk.

Google the issue, the best resources are user forums. Manufacturer support is also close to useless in almost all cases. I've never spoken to a vendor technician who knows enough about a problem to solve it. Their main function is to convince people to reboot or blame another vendor.