i dunno, like i said i had the same mobo and it didnt work so i took it back and got my NF7-S (probably the best thing i did, NF7-S kicks ***) anyway. make sure you have all the connectors inserted all the way, another comon mistake is there is a 4 pin power connector for the new boards, make sure you have this pluged in. my board did boot once, with my sempron 2500 and posted and i got into the bios, after i restarted it never booted again. no matter what i tried. It also could be that your video card isnt compatable with the mobo, sounds stupid but sometimes it happens. see if you can get ahold of and old PCI vid card and try that out. also try posting it with nothing but the ram, cpu, and vid card in.
here is a link that i used to help make sure that my cpu wasnt burnt out
page 9 and 10 are the ones youl be paticularly interested in.
also make sure your power supply is putting out the correct voltages.
white -12v (i think)
Run through your manual to make sure the jumpers are set properly. and DO NOT POWER UP WHEN RESETING THE CMOS!
all you need to do is set the jumper to the reset position, wait a couple secs, and the change it back. if you power up the system there is a chance that you can wreak the CMOS chip, rendering the motherboard usless, and perhaps even voiding thw warrenty (of course dont tell them and youl most likely 99.9% get away with it). The athlon cpu (yours) and my sempron have the same architecture, they are basicaly the same cpu, so it is possible that this certain motherboard just doesnt like the cpu.