How do I delete user names from Knowledge Adventure Jumpstart First Grade?

I had this same problem. Tried uninstalling, deleting everything, restarting, and reinstalling, and still the names were there! I finally found this on Knowledge Adventure.

Recommendations:
· JumpStart: Most of the JumpStart programs have a keystroke combination like CTRL+D+D to delete one user at a time from the sign in screen. See the manual for more information regarding the software. Other JumpStart programs have a delete button directly on the sign in screen.

For me CTRL+D+D didn't work, but I tried CTRL+Delete, and it did. Phew!