External drive would be the easiest choice, as reedo_43 said.
Barring that, you need to get both computers to see each other.
Doing that could work as long as you do following:
manually set IP's for both computers to same subnet.
As example:
192.168.0.1 and 192.168.0.2
subnet 255.255.255.0
After that, you would most likely need to share the drive on XP laptop or.. if you happen to have same username on both... you might not need to.
open windows explorer (windows+E), since network browser can be wonky.
You can set folders/drives to be shared with right clicking on them and selecting sharing option, where you just need to provide a name under which you share it.
type following in the address bar, assuming that the XP machine was set to be 192.168.0.2:
192.168.0.2\sharename
If you use same username on both and never disabled default shares, you could do:
192.168.0.2\C$ (where letter is drive letter to access whole drive, kind of needs that same username on both and you to be administrator too)
And above assumes that you do not have any special firewall rules blocking file sharing.