I'd say check for a bios update. See if that resolves the issue. Could be a fault with the stock bios. Also, you're sure u using dimm 0? Confirm in the booklet that the one u plugging into is in fact dimm 0.And you can try other memory sticks as it could be an incompatibility with those particular sticks with that board.
Wow...misfortune just seems to follow you with these parts nowadays.If you can, try using the RAM in a single-channel config, and see if all 4GB are recognised.Then try all the dual-channel configs as described by the mobo manual. You should followthe goodly Cap'n's advice and update the BIOS. A great majority of BIOS updates nowadaysare CPU microcode and RAM related....and who else will know the BIOS was updated?
Any luck with this hater?