Cannot access shared files and folders or browse computers in the workgroup with Windows XP

SYMPTOMS
On Windows XP-based computers that are configured as members of a workgroup in a peer-to-peer network environment, you may experience one or more of the following symptoms:

• You cannot access shared folders or files.
• You cannot locate other computers in the workgroup.
• You receive the following error message when you double-click the workgroup in My Network Places:

Workgroup Name is not accessible. You may not have permission to use this network resource.

Note In a peer-to-peer network, each computer is equal and can initiate communications. In this manner, it differs from a client/server network.

CAUSE
This behavior may occur if all the following conditions are true:

• NetBIOS over TCP/IP is not turned on (enabled) on one or more computers in the workgroup.
• The Computer Browser service is not started or is turned off on one or more computers in the workgroup.
  

This behavior may also occur if File and Print Sharing for Microsoft Networks is not installed or is blocked by Windows Firewall.

RESOLUTION

Method 1: Enable NetBIOS over TCP/IP and start the Computer Browser service
To resolve this issue, make sure that NetBIOS over TCP/IP is turned on and that the Computer Browser service is running on each computer in the workgroup. To do this, follow these steps.

Step 1: Enable 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. On the right side, right-click Computer Browser, and then click Start.
5. Close the Computer Management window.

Method 2: Install File and Print Sharing and make sure that it is not blocked by Windows Firewall

Step 1: Install File and Print Sharing for Microsoft Networks

1. Click Start, click Run, type ncpa.cpl, and then click OK.
2. Right-click Local Area Connection, and then click Properties.
3. Click the General tab, and then click Install.
4. Click Service, and then click Add.
5. In the Network Service list, click File and Print Sharing for Microsoft Networks, and then click OK.
6. Click Close.
   

Step 2: Make sure that File and Printer Sharing is not blocked by Windows Firewall

1. Click Start, click Run, type firewall.cpl, and then click OK.
2. On the General tab, make sure that the Don't allow exceptions check box is not selected.
3. Click the Exceptions tab.
4. On the Exceptions tab, make sure that the File and Printer Sharing check box is selected, and then click OK.

Source: Support.microsoft.com