I have a Dell XPS 410 that immediately reboots itself when powered on. A few times it has allowed me to use my Linux Mint disc for a little while before spamming the shutdown menu then rebooting. The majority of the time it immediately, repeatedly reboots itself, reaching only the black screen that checks my devices, just before the computer asks me whether I would like to boot from an inserted disc. The computer will also reboot itself when I'm in the BIOS, if I manage to enter the BIOS. I disconnected all peripherals as well as removed the RAM sticks and graphic card, but the issue still occurs. I also tried a brand-new power supply and a new motherboard, but they didn't work either. I believe that just leaves the CPU and power switch board. How likely is the CPU responsible for this issue? Could it be the power switch board?
Specs: http://postimg.org/image/rzues2zqt/ (Note: Currently, there is no OS on either hard disk.)