I am repairing a Samsung R730 for a friend. The laptop keeps rebooting at the BIOS splash screen. I tried swapping out ram and booting without battery, hard drive, or optical drive. I also disassembled the laptop and cleaned/applied more cooling paste to the CPU and GPU. This produced the same results. I ordered a refurbished motherboard and cpu off the internet. I swapped the hardware tonight and same issue persists. I am lost on next steps. Any assistance will be appreciated.