How do you share a printer on a home network when you have windows xp on one pc and vista on another?

Turn off the Firewall....Hardreset(Reboot) att the devices....wair for 1 min..then restart... In the main computer where the printer is installed, just go to the Printer folder inside of Control Panel. Right click your All in one printer and then Click Sharing. Click on Share this printer in the window that opens and then hit OK. Get the IP address of your computer, go to Start, Run, type "cmd" enter, type "ipconfig" enter. Write down where it says "Local Area Connection" IP address: "numbers with dots". After this, move to the computer without a printer. In the other computer, go to Start, Run, type "\\ipaddress\" where ipaddress are the numbers of the 1st computer. When a windows opens asking for a user name and password input those credentials from your computer. If it doesn't ask it will be even better. Now with this command you will open a folder and the printer will be there. Double click the printer and now the 2nd computer will be able to use it. BTW, both computers have to be in the same WORKGROUP. to check this: Right click My Computer icon on the desktop, go to properties, Computer name tab. There you can see the WORKGROUP name and even change it.