Installed new ram same brand and type as existing ram, computer did not see it removed old ram restarted computer it showed new ram, reinstalled old ram computer does not see ram total, aridgonal amount 2 one gig sticks added 2 one gig sticks of corsair pc6400 ddr2 800mhz moboard can handle 10.7 gig.

motherboard model?
CPU?

can it not see it in both the BIOS and the OS?

What OS?
Is it a 32 bit OS?

Windows 32-bit wont use more than about 3gb of ram, no matter how much you have installed

Im using windows xp pro 2002

Yeah, it will not use all your ram to full effect, it will only use about 3gb. Thats normal.

do I have to use vista to get 64 bit or is there a upgrade for xp pro

Xp pro x64 is crap. Nothing runs on it

The Vista 64 bit version(s) aee much better, but i dont think there is any upgrade path to it.

There aint any real need to get the full amount available. Most games etc.. wont even take advantage of 4gb+ . Dont worry about it