Ever try to open up a file with an unknown extension and get an annoying popup asking you if you want to use a web service to see what the appripriate program is to open that file? Me too! Here's how to get rid of that useless popup:
I stole this from http://www.microsoft.com/technet/prodtechnol/winxppro/maintain/xpmanaged/09_xpfil.mspx
To Disable the File Association Web Service by Setting a Registry Key
1. Open Registry Editor by clicking Start, clicking Run, and then typing regedit.
Caution Incorrectly editing the registry may severely damage your system. Before making changes to the registry, you should back up any valued data on the computer. You can also use the Last Known Good Configuration startup option if you encounter problems after manual changes have been applied.
2. Navigate to the following registry key:
3. Point to New in the Edit menu, and then click DWORD Value.
4. Type the following name:
5. Click the new entry (NoInternetOpenWith), and then select Modify in the Edit menu.
6. Ensure that Hexadecimal is selected, and then for Value data, type:
7.Close Registry Editor.