If i type ipconfig/all is the Physical Address refers to the serial address/number of the CPU or the Processor? I'm running Windows XP.
It's actually the unique MAC address of your network card, or other network interface.
edit: it's not clear whether you're after network details or cpu details here -- maybe you could expand the question by describing what you want to achieve.
edit: you might be able to get what you want through WMI. If you're looking for a serial number and/or asset tag for the hardware, you might be lucky with this. For the baseboard you might be able to use Win32_Baseboard. And for the CPU processor id, you might get what you need with Win32_Processor. If you're not sure about WMI, or haven't used it before, maybe try WMI Creator, as it's very helpful.
However: it's still not clear what you want to do with it, and none of these may be what you need. Check, for example, this other StackOverflow question.
Hope that helps a bit.
As Tim said, IPConfig deals with network settings and is completely unrelated to your CPU.
At one time Intel did have an actual serial number for their processors, but this was abandoned for a host of security reasons.
Namely, people threw an absolute fit over the idea that software could identify the actual machine that was used to create documents etc. Little things like Privacy would easily be subverted.
Not only that but the idea of a unique serial number per chip couldn't meet the stated goals of actually saying the machine was who it said it was. Basically, it could easily be duped. http://www.schneier.com/essay-187.html
Now, there is something called a Trusted Platform Module (TPM) which is built into some motherboards that provides a unique encryption key. However, those modules aren't that common and, even when found, aren't normally turned on.
So, if you are trying to find a unique id for the machine as a whole, the best you can hope for is to use the network adapters MAC address. Those are unique, however, they can also be spoofed. And, network adapters can be swapped out on a whim thereby changing the address.
Perhaps if you posted what you were trying to accomplish we could better guide you.
I'd try with
wmic cpu list full
or also with