In order for your computes to ping each other on a network level, they have to be on the same network. Go to start menu, right-click Computer(Vista) or My Computer(XP) and select Properties. In Vista, change the workgroup name so they're the same on both computers. In XP, in the properties windows go to Computer Name tab and change workgroup name on both computers. Both computers are no on the same network, but the computer must be restarted for changes to take effect. Also, if you want to enable printer and file sharing, for XP open windows explorer (start menu>all programs>accessories>windows explorer). In the left window find the C drive and right-click and choose "sharing and security..." and in the properties window under Sharing tab, click the bottom sentence. In the "Network sharing and security" window, check the "Share this folder on the network" box and then name the folder what you want. If you want, you can allow others on the network to change files by click the "Allow network users to change my files" box...otherwise, leave it unchecked. Click OK and you now have a network sharing folder. Go through the same process on the other computer (if running XP) to enable printer and file sharing on there too. On Vista..well, you'll have to look it up cause I can't remember at the moment. I use Win7 and the features are slightly different I believe.