We've heard from a lot of people who have problems with machine names not showing up in the My Network Places or Network Neighborhood applet. There are a number of causes for this, but the most common are: NetBIOS isn't enabled, or the Server service (file and print services) isn't enabled on the interface. You can only disable NetBIOS on Windows 2000 and Windows XP computers, but you can disable file and print sharing on any Windows computer. On a Windows XP computer, perform the following steps to check your setup:

1. Click Start and right click on My Network Places and click Properties.
2. In the Network Connections window, right click on your Local Area Connection and click Properties.
3. On the General tab, find the File and Printer Sharing for Microsoft Networks entry. There should be a checkmark in the checkbox to the left of this entry if you want your computer to show up in the My Network Places or Network Neighborhood applet.
4. Scroll down to the Internet Protocol (TCP/IP) entry and click on it. Then click on the Properties button. On the Internet Properties (TCP/IP) Properties dialog box, click the Advanced button.
5. In the Advanced TCP/IP Settings dialog box, click on the WINS tab. Make sure that Enable NetBIOS over TCP/IP is selected.

If you have NetBIOS and the server service enabled (by enabling file and printer sharing), then your computer should show up in the My Network Places or Network Neighborhood.