Dell PowerEdge R720 Reboots At POST Screen

We have a Server that was working absolutely fine for months on site, i would say even a year since its installation, then this week it suddenly developed a CPU Internal Error.

When the server boots up it does a Memory Configuration successfully, it then loads iDRAC successfully, but when it gets to the POST screen it seems to freeze and then reboots on a loop.

To explain further, it will load the POST Screen and the cursor will remain flashing but you cannot enter any menus or press any button combinations on the keyboard, if you are able to press F2, F12 etc before it freezes it will simply show in the top right corner it is "Loading *Whatever option you chose*" and the cursor on the post screen will still blink but it will then reboot again.

We have tried the classic turn the power off, hold the main power button in for 20 plus seconds and turn on again, but nothing.