Im currently building a new pc using a dfi nf4 ultra-d board and g-skill pc4000 ddr. When i first switch on the pc i get a cmos checksum error, if i then go into the bios and change something (anything) the pc doesn't even post anymore, i just get constant long beeps abot 4 secs apart which i believe indicates a memory fault. Only way to boot it then is to reset bios (again, going back to checksum errors). I've tried all the slots and using each stick by itself. No joy. Any help would be greatly appreciated.