As they are not yet common, you would be very concious of the fact that you
had a 64 bit system. The standard processors take advantage of the 32bit
architecture.
XP Home is 32 bit only. XP Pro is availabe in 32bit or 64 bit but the 64
bit version requires a special processor to operate.
Start> Run > and type in winver
Click OK.
If the version screen does *not* say 64bit, you have 32bit.