Hmm sounds like the actual BIOS update went bad, which usually shouldnt happen. Not sure whether flashing from win7 is a good idea but maybe you can kind of initialize a boot to flash from there. If all fails you - or someone who does this on a regular basis - can still burn a new rom (like this selfmade one here http://www.eeweb.com/project/circuit_projects/pic-and-eeprom-programmer ) with a working BIOS.