Confusion between 32bit & 64bit OS

[satyamy]

What is the difference between 32bit and 64bit OS
also
What is the difference between 32bit and 64bit Computer
I have WinXP_SP2
how can i find out my OS is this 32 or 64......?
i think mine is 32........... just guessing...........
from where can i get 64bit OS
n
wht is the config reguired to run a 64bit OS
Pls tell if u have any idea...........?

[satyamy]

oh thanks a lot