JSI Tip 9841. Freeware selectively clears the Open With list on Windows XP.

Download and unzip OpenWithClear.zip.

When you double-click OpenWithClear.exe, a GUI open that allows you to select a file extension from the Extensions drop-down box. When you do, the Dynamically assigned programs box will contain the dynamic entries in the Open With list.

The author, Doug Knox, provides a Clear button, to allow you to select one or more  programs to remove, and a Clear All button to remove all dynamically assigned entries.

NOTE: This program should work on any Windows operating system if the VB 6 runtime library, which is included in Windows XP, is installed.