It sounds like your RAM Disk is running without administrator rights. Its licence key is stored in the driver's configuration, so entering it requires an elevated session (unless the "Allow user access" option was enabled by an administrator beforehand).
To resolve it:
- Quit the RAM Disk application completely via File > Exit in the main menu. This is important, because the cross [X] button only minimises the application to the notification area, so make sure to use File > Exit.
- Find RAM Disk in the Windows Start menu, right-click it, and choose Run as administrator.
- The Help > Enter Licence Key menu item should then become available, along with all the other options.
If that menu item is still greyed out after launching as administrator, please let us know whether any error message appears when the application starts. It would suggest there is a different issue with the driver connection, and we will promptly look into it.