In Windows XP the TCP/IP stack can be reinstalled rewriting all registry entries and files having the same effect as reinstalling TCP/IP in earlier windows.
1. Click Start > Run
2. In the open field type command if command gives an error type cmd instead
3. In the command window type netsh int ip reset C:\reset.txt press enter
4. After a few seconds it should return the the prompt if you see an error such as 'NETSHH' is not recognized as an internal or external command, operable program or batch file. Ensure you have typed the command correctly and that you have windows XP
5. Click start > Search
6. In the search window click the all files and folder link on the left
7. In the all or part of the file name field type nettcpip.inf
8. In the look in field ensure the drive that windows is installed on is selected if you don’t know which one select My computer
9. Click the more advanced options button and ensure search system folders, search hidden files and folders and search subfolders are ticked
10. Click search
11. It may return more than one file they should all be 24 KB choose one right click on it and select install from the menu. The screen may flicker once you have clicked install restart the computer and check to see if you are able to get webpages.