The PC booting and then seemingly halting to then reboot is most often a RAM issue where the PC (with a recent motherboard) wants to check the RAM to see if the motherboard can communicate with said RAM. This is often the case when you use RAM that needs a so-called XMP profile with RAM from a brand that isn't supported by the brand of motherboard you have.
If the issue persists, set everything concerning RAM sticks to "Auto" in the BIOS. Turn on the PC and use it for a short while (ten minutes to a couple of hours), shut down the PC and reboot to go into the BIOS and adapt the RAM settings to their value. After that, the PC will boot in a normal fashion.
If none of the above apply, shut down the PC and re-seat the RAM sticks to see what gives.