Hello Clark, and welcome to Seven Forums.
If you do not see a Merge
option when you right click on the REG file, then you will need to check in Default Programs
to set the reg
file extension to have it's Current Default
program set as Registry Editor
(C:\Windows\regedit.exe). Afterwards, try merging the REG file again.
If afterwards, you also have other file extensions opening with notepad as well, then you could use the tutorial below to restore the default associations for that file extension. Default File Type Associations - Restore
Hope this helps,