There could be a few reasons for this. It's possible that Java was not properly installed on your computer, or that the installation was interrupted during the reboot. It's also possible that your computer's firewall or security settings are blocking Java. Lastly, if you recently updated your operating system or Java, there may be compatibility issues causing Java to not work after a reboot.
If you don't have Java installed on your computer, you can visit the official Java website and download the latest version. Make sure to follow the installation instructions carefully and ensure that Java is enabled in your browser settings. If you already have Java installed, try reinstalling it to see if that resolves the issue.
You can try adjusting your firewall settings to allow Java to run. You can usually find these settings in your computer's control panel or security settings. Make sure to only allow Java to run on trusted websites to ensure your computer's safety.
Each browser has different settings for enabling Java, but you can usually find them by going into the browser's settings or preferences and searching for "Java". Make sure that Java is enabled and that there are no restrictions for running Java on certain websites.
If none of the above solutions work, it's possible that there is an underlying issue with your computer's operating system or Java installation. You can try updating your operating system and Java to the latest versions, or contact a computer technician for further assistance.