Brand bew Asus P5Q Pro motherboard (no cheap trash here!) with 2 sticks of new Crucial BL12864AA804.8FE5. Refused to complete the Vista install so tried again with a couple of sticks of Kingston - no further problems. Checking the Asus book of words is says that Crucial BL12864AA804.16FD or BL12864AA804.16FD3 is approved. Is the difference enough to make the board reject the memory??