How do I Fix the Java Error Can't Find Main Class?

Uninstall Java
1. Click 'Start' and select 'Control Panel.'
2. Click 'Programs' and select 'Uninstall a program.'
3. Browse through the list of programs and locate 'Java 2 Runtime Environment SE' or any similar version of Java.
4. Click 'Uninstall' and follow the on-screen prompts to uninstall Java.
Reinstall Java
5. Visit the Java download page (see Resources) and click the download link for the Java file that matches your operating system. Save the file to your desktop.
6. Close your Web browser and any other open windows on your computer.
7. Double-click the Java installation file on your desktop. The welcome dialog box appears. Click 'Install.'
8. Click 'Next' and allow Java to fully install on your computer. Click 'Close' and restart your PC.