To check you have this problem, try the folowing steps:
When you try to ping anything, ping fails with error code 10091 or error message "Bad IP address"
When you try: Start>> Run>> winipcfg
You get "Fatal Error:Cannot Read IP configuration"
This error occurs if your computer has had the WINSOCK2 update applied and then partially uninstalled.
Start>> Shut Down>> Restart in MS-DOS mode
At the command prompt, type the following commands, pressing ENTER after each command:
cd c:\windows\ws2bakup
ws2bakup.bat
exit
Restart...
Change c:\windows to a different folder if Windows is installed in a different folder.
If you are prompted to abort, retry, or fail the operation, press A. This causes the Ws2bakup.bat to continue restoring up all the necessary files.
If you receive error messages when you run the Ws2bakup.bat file stating that some programs cannot be run outside of Windows 95, disregard them.