How to Reinstall Java

Uninstall existing JRE software
1. Click the Windows 'Start' button and select 'Control Panel.' Depending on your Start Menu configuration, this item may be located within the 'Settings' folder.
2. Open your system's Programs utility. In Windows Vista or Windows 7, the icon is labeled 'Programs & Features' or 'Uninstall Programs,' depending on your folder settings. The icon is labeled 'Add or Remove Programs' in Windows XP.
3. Locate your current Java installation in the list of programs.
4. Click the program name and click the 'Uninstall' button on the menu bar near the top of the screen. In Windows XP, click the 'Remove' button that appears next to the program name instead.
5. Follow the on-screen prompts to remove the current Java installation from your computer.
6. Restart your computer after the uninstallation process completes.
Install current JRE software
7. Open a Web browser window and navigate to the 'Downloads' page on the Java website.
8. Click the link labeled 'Windows 7/XP/Vista/2000/2003/2008 Offline' and save the JRE installer file to your computer when prompted. Close all open browser windows once the download completes.
9. Double click the icon of the installer file you downloaded in the previous step.
10. Click 'Install' on the first installer screen. Depending on your system setup, you may be presented with a screen that allows you to install optional software, such as the Yahoo! Toolbar, after clicking 'Install.' Check the box next to the name of any program you want to install along with the JRE, and then click 'Next.'
11. Click 'Close' after the installation process completes to close the installer program. You have successfully reinstalled the Java Runtime Environment software.