http://support.microsoft.com/kb/318030
You cannot access shared files and folders or browse computers in the workgroup
Step 1: Turn on NetBIOS over TCP/IP
1. Click Start, click Control Panel, and then click Network and Internet Connections.
2. Click Network Connections.
3. Right-click Local Area Connection, and then click Properties.
4. Click Internet Protocol (TCP/IP), and then click Properties.
5. Click the General tab, and then click Advanced.
6. Click the WINS tab.
7. Under NetBIOS setting, click Enable NetBIOS over TCP/IP, and then click OK two times.
8. Click Close to close the Local Area Connection Properties dialog box.
9. Close the Network Connections window.
Step 2: Start the Computer Browser service
1. Click Start, right-click My Computer, and then click Manage.
2. Double-click Services and Applications.
3. Double-click Services.
4. In the right pane, right-click Computer Browser, and then click Start.
5. Close the Computer Management window.
