Whenever this has happened on any machine I've dealt with, it meant the keyboard was dead. Try replacing it first. I do believe that usually the BIOS default is to ignore all errors except keyboard faults.
Tom
This happens to me too, when I disable legacy USB support in the BIOS and leave a USB hug or drive plugged in. My computer will hang there are POST displaying my system information and stays there.
Try unplugging all unessential hardware. So you only have your monitor, keyboard and mouse connected to you computer and try to boot it.
So you get the POST screen, and it freezes? Sounds like an HDD failing to detect or an bad stick of RAM when trying to do that. An keyboard is an possibility, but mainly I'd think that unless you get the "Keyboard not found" error, it's not the keyboard.