When you double-click on an unknown file type in a default installation of Windows XP, you are presented with two choices for what to do next: select a program from a list of programs installed on your PC *or* use the Microsoft Web Service to figure out which program will open the file. Since I’ve never known anyone, anywhere at any time to use the stupid “Web Service” lookup thingy, this makes Windows’ default behavior pretty annoying, as it adds an extra step in the file-opening process. Luckily, it’s really fast and easy to disable the Web Service prompt:
1) Click on Start > Run. Type regedit into the Run: box and click OK.
2) Navigate to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion > Policies > System.
3) Right-click in the right pane and select New > DWORD value.
4) Name the new DWORD value NoInternetOpenWith and set its value to 1.
5) Close Regedit. No reboot is necessary!