Sorry for the late reply.
Create a restore point System Restore Point - Create
I will show you how to backup the registry in a couple more steps.
In the start menu search box type regedit
and click on it in the search results to open up the registry editor.
Navigate to HKEY_CLASSES_ROOT\Directory\Background\shell
Now we will back up the registry Registry - Backup and Restore
Right click on Directory and click on Export.
Give it a name and click on Save (I usually save them to the desktop and tell them done and then you can either store it in a folder in your documents folder or delete it).
Now we will add a program (I am going to use Firefox as an example)
Right-click on shell go to New > Key and click on it.
In the New Key #1 Box Add Your Program Name That You Want to See in the Right-Click menu here I put Firefox.
Right-click on Firefox go to New > Key and click on it.
In the New Key #1 Box Add command
Now you need to navigate to the programs .exe then push and hold Shift + and Right click on the program .exe and click on Copy as Path.
Go back to the registry editor make sure you click on command on the left side and then on the right side Double-click on Default.
In the Edit String box in the value data Paste or Ctrl + V the path of the program .exe and click on OK.
You should have your program in the right click menu(you may have to logoff/logon or restart to see it in the menu)
If you would like add icon to it follow this tutorial Context Menu - Add Shortcuts with Icons
If something is confusing let me know and I will try to straighten it out for you.