How can I prevent others from viewing or changing my VBA code?

If you use Excel 97 or later... Activate the VB Editor and select your project in the Projects window. Then choose Tools - xxxx Properties (where xxxx corresponds to your Project name). In the Project Properties dialog box, click the Protection tab. Place a checkmark next to Lock project for viewing, and enter a password (twice). Click OK, and then save your file. When the file is closed and then re-opened, a password will be required to view or modify the code.