To check which version of Java you have on your Windows computer, you'll need to open the Command Prompt.

To test the Java as home directory go to Window -> Start -> Run open cmd and click ok. In command prompt type java and press enter then you should see java installed on your system.

Now, visit the official Java web page to re-install the Java application. Once you have re-installed the applet, check if the Java control panel is not found issue is fixed.

If Java is not recognized as internal or external command, you need to make sure that the installation is not problematic and its path is recognized as system variables.