When I right-click on a file, in File Explorer, and select Send to > Mail recipient I get a message box saying:

There is no email program associated to perform the requested action. Please install an email program or, if one is already installed, create an association in the Default Programs control panel

I have done as instructed with no results

This issue may occur if the Outlook registry key is corrupted. When other programs try to use the Outlook Simple MAPI interface, they cannot retrieve the required information from the registry.

You must first remove the corrupted Outlook registry key, and then perform a Detect and Repair operation to have Outlook rebuild the key. To do this, follow these steps:

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then press ENTER.
3. In Registry Editor, locate the following subkey in the registry: HKEY_LOCAL_MACHINE\Software\Clients\Mail\Microsoft Outlook
4. Select the subkey, and then press DELETE.
5. Click Yes.
6. Quit Registry Editor.
7. Start Outlook.
8. On the Help menu, click Office Diagnostics.
9. Follow the instructions on the screen to complete the repair.