If tomron's suggestion fails to heal it completely try the following

 

Open a command prompt and type the following

 

netsh winsock reset

 

hit enter, then reboot.

 

 

If this fails to give results try the following

 

 

Step 1: Delete the corrupted registry keys

 

1. Click Start, and then click Run.

2. In the Open box, type regedit, and then click OK.

3. In Registry Editor, locate the following keys, right-click each key, and then click Delete:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ Winsock
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ Winsock2 

Only delete keys (folders) in RED.

4. When you are prompted to confirm the deletion, click Yes.

 

5. Reboot

Note Restart the computer after you delete the Winsock keys. Doing so causes the Windows XP operating system to create new shell entries for those two keys. If you do not restart the computer after you delete the Winsock keys, the next step does not work correctly.

Step 2: Install TCP/IP
1. Right-click the network connection, and then click Properties.

2. Click Install.

3. Click Protocol, and then click Add.

4. Click Have Disk. 

5. Type C:\Windows\inf, and then click OK.

6. On the list of available protocols, click Internet Protocol (TCP/IP), and then click OK. If Internet Protocol (TCP/IP) does not appear, follow these steps:

a.  Click Start, and then click Search.
b.  In the Search Companion pane, click More advanced options.
c.  Click to select the following three check boxes:

     • Search system folders
     • Search hidden files and folders
     • Search subfolders 

d.  In the All or part of the file name box, type nettcpip.inf, and then click Search.
e.  In the results pane, right-click Nettcpip.inf, and then click Install.
 
7. Reboot