Here is what I found in the Help file Seb.
How to Remove Programs from the "Open With" List View products that this article applies to.
Article ID : 258860
Last Review : September 28, 2004
Revision : 2.1
This article was previously published under Q258860
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SUMMARY
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SUMMARY
When you right-click a registered file type, you can use the Open With command to select a program to open the file. Each program you use is added to the Open With list for that file type, even if the program you are using is unable to open the selected file type. For example, if you select Microsoft Paint (SPaint.exe) in the Open With dialog box when you open a text document (a file with a .txt extension), the Paint program is listed in the Open With list for all text documents, even though Paint is unable to open text documents. This article describes how to remove programs from the Open With list.
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WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

The programs on the Open With list for each file type are independent of that file's registered program(s). To remove items from this list, locate the following registry key
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ Explorer\FileExts\.extension\OpenWithList
NOTE: The above registry key is one path, it has been wrapped for readability.

where extension is the file extension for the file type whose Open With list you want to modify. Delete the value in this key that represents the program to be removed from the Open With list.
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APPLIES TO
Microsoft Windows 2000 Server
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Professional Edition
Microsoft Windows Millennium Edition

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Keywords: kbhowto kbenv kbui kbfaq KB258860

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Seb_Chen

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