nat3wall,
just been doing some further research on this. There were various versions of this motherboard - Stingray, Yale, Oxford - and it seems that not all of the versions took 1GB sticks - and there seemed to be some suggestion that someone at HP got it wrong, and the boards will only support 4x512. I know this does not help with the extra RAM you bought, but I thought you should know. Google it and see if you can find anything else. I checked on the Asus site for the board, but got nothing. It was obviously a proprietary board for HP/Compaq.