I'am worried, that i'am encountering a serious problem with my MB.
I have 4 DIMM Slots (A1,A2,B1,B2). Normally i used two kits of 2GB (KIT 2x1GB) DDR2 800MHz PC6400 A-DATA Extreme Edition Vitesta = 4GB in total.
After i installed my new CPU cooler, i realised my system only running with 2GB's of memory, while all 4 ram modules are in MB. After trying all the rams/slots separately, i found out that slot A1 and A2 is not working at all - doesnt matter what RAM i plug in. (only A2 slot is working randomly - 1 of 10 tries)
Yep it's a bad board in that respect. If you RMA it to Asus I wish you lots of luck.
You will need it.
Asus tech support and RMA are disconnected and they really don't fix things that are sent into them. They just do a test and if it works send it out to someone else.