RAM not reading...?

Wondering if anyone might know what I am dealing with....

WinXP SR3
XFX nForce 750a SLI MoBo
Had 1GB RAM in each of the (4) Slots, system was registering 3.25GB.
Now, I am trying to upgrade the RAM and can go to 8GB, so I plunk in
(4) bars of Kingston HyperX 800MHz / 2GB each and yet it is still showing 3.25GB.... Matched the DDR2 and even double-checked with XFX to see if I could go up.

Is there something that I am missing here?
Is there a CMOS setting that I need to toggle?

Looked but did not see anything glaring at me....

 

ECC or non ecc?

 

The reason windows is not seeing the extra ram is because you are running a 32-bit version of windows. For windows to see the ram, you have to be running the 64 bit version. Looks like it's time for an upgrade to windows 7 (64-bit).

BTW, what does your BIOS show you have installed? I'll bet the BIOS shows all 8gb.

 

Here.

Longer version of what abekl just said.

 

If you ever feel the urge to dig a little deeper, there's an interesting article here.

 

Thank you all wise ones.... this I did not know.
Well, on the bright side, I'm all set in RAM for Windows 7 -- whenever I can move up to that level!!!

Thanks again.

 

Make sure you install the 64-bit version