Sometimes when connecting a Vista based PC to a XP based network, it may happens that your Vista PC is unable to detect the other XP based PC, making File/Print sharing iimpossible
If you are experiencing a hard time finding any other computers on your network, make sure that the option named "Password Protected Sharing" is disabled. Follow the instructions to see if it's on.
- Control panel
- Network & Internet (or Network & Sharing Center if you have "Classic View" enabled)
- Network & Internet Sharing Center
- Scroll down until "Password Protected Sharing" appears and tick it off.