Removing programs from "open with"

Click Start, Run, Type REGEDIT Navigate to the following key:HKEY_CURRENT_USER \ Software \Microsoft \ Windows \ CurrentVersion \Explorer \ FileExts

Find the extension you wish to edit and click on the [+] sign to expand OpenWithList (in the right pane, you will see a list with the programs, like “paint.exe”, “notepad.exe”, etc).

Use the File, Export option to back up the key.
Click on the one you wish to delete and press the delete button.

Still some items may show up in the Openwith lists, which comes from the HKEY_CLASSES_ROOT registry key, which is common for all the user profiles. You may
remove the entries from the following key:HKEY_CLASSES_ROOT\ .xxx \OpenWithList where xxx is a file extension.With that removed, Windows may still show some default open-with lists.Depending upon the file type, the openwith listing is generated from the subkeys under:
HKEY_CLASSES_ROOT \SystemFileAssociations \ <Type>\

Simply put, don’t remove this part as it affects many file types, not aparticular one