Will someone please explain in detail, I can link my 2 xp computers but not my xp and vista with my crossover cable?
Have a look there: Windows Vista Help: Set up a computer-to-computer (ad hoc) network
It explains how to set up a ad-hoc network, then follow the link to share files.
Hope it helps.
Ad hoc networks can only be wireless, so you must have a wireless network adapter installed in your computer to set up or join an ad hoc network