I had a big problem with a new mobo an ASrock 4coredual-vsta it would not boot up at all but the fans ran as soon as power was switched on. I exchanged the board for another one this one boots up OK - almost! i'm getting a message on startup 'MAC address are invalid in both CMOS and flash!' press F1 to Resume after pressing FI boot up completes. I was able to install windows XP Pro OK. I'm still installing drivers etc but I think an invalid MAC address will give me problems when I want to network the PC & connect to internet. Any way I can sort the mac address I have been unable to contact ASrock some problem with their website customer service connection.