New
#81
Just came across this, First thing you need to check with stuff like this is your Motherboard Chipset.
For instance I have an Old Dell M90 Precision - Dell says you can stick 4GB in it - You can, however the Intel Chip set that is in the M90 - the 945 cant address over 3.3GB regardless of OS installed.
I would be that HP just chucked in a newer models MOBO that can address all the space...
I have seen this with many off the shelf systems that you can buy from PC World...