C400 screen flashes white randomly

My C400 started having problems yesterday after I updated to the version 12 (?) bios. It didnt happen immediately after updating, but a few hours later. Anyways, the screen will randomly flash white and sometimes will become garbled, but it comes back to normal a second or so later. It boots to windows fine, I plugged it into my 2001FP and it works fine on it, and it is not a windows problem because if I go to the bios it does it there too. I have reseated the flex cable several times to the motherboard connection and reseated it where it connects to the LCD and where it connects to the inverter. I'm stumped as to what the problem is... I have tried to roll back the bios to an early version but it says that it wont because it is newer. I really hope it is not the LCD because it normally works fine, it will just flash white every once in a while (every 10-20 seconds or so). Help!