Hi Donkey, thanks for the quick reply.

I baught a matched pair of corsair value select ddr2 4gb in total 2x2gb sticks. I inserted both into slots 1 & 2 (yellow) as shown in the mobo manual. System would not boot! but when I removed one of the modules it did boot. If I insert one module into any of the slots it boots. The problem is when both memory modules are instaled together the thing wont boot.