Mine does that too after bios but I think the 3rd time it booted Or few times I shut it down after the 2nd time it did that and when it fired up it told me overclock settings failed and let me into bios. Did you try hitting the del key the moment you try to fire it up even before video shows up? Or pull all the add on cards usb printer and just use keyboard video. No Lan bare min start up and clear bios first then pull the bat and wait the 15 min. Replace the bat and make sure the clear jumper has been returned to the normal position. then try booting. If none of this helps you will have to ask someone else because I am out of answers then.
good luck