Can't get past POST, BIOS.

Hey guys, so I tried using my MOBO's (ASRock) OC Tweaker, accessed through my UEFI BIOS screen, to bring up my i7 3770k to 4.8ghz... I've been using it at 4.4ghz stable for a while now and figured why not try pushing it to 4.8. Anyways, I made the changes, hit "Save and Exit"... it took me back to my POST Screen and froze there. Eventually I tried going back into my UEFI to no avail. I forced shut down and tried again to get into my UEFI by hitting DEL, but it takes me to a black screen with a "_" in the top left and "A9" in the bottom right... it doesn't get anywhere past that.

Anyways, I'm guessing there's a problem with my motherboard since I can't even get into my BIOS, but is there any way I can fix this? Thanks in advance.