problem with crucial ram

[BigDools]

Crucial Ballistix 2GB (2x1GB) DDR2 PC2-8500C5 1066MHz Dual Channel Kit (BL2KIT12864AA1065)
Asus P5N-E SLi nForce 650 (Socket 775) PCI-Express DDR2 Motherboard

when i do the following setup memtest is bringing up loads of errors and i get crashes in windows.
Dimm_A1 <1 stick
Dimm_A2 <none
Dimm_B1 <1 stick
Dimm_B2 <none

if i remove the stick from B1 everything is fine ive also tried both stick in A1 so i dont think its the ram ive got a feeling its the B1 slot .

im currently running

Dimm_A1 <1 stick
Dimm_A2 <1 stick
Dimm_B1 <none
Dimm_B2 <none

this setup works fine no errors in memtest either.
im a little unsure how the dimm slots work am i doing wrong useing 1 stick in A1 and another in A2?

 

[BigDools]

ive checked the ram seperatley and it fine its just the 2nd yellow slot i does not like it .

im running both sticks in the black slots and it seems fine like this no errors in memtest had no crashes yet so it has to be that slot.

 

[BigDools]

yeah im running the latest bios mate . im just going to use the black slots its working fine