Easiest thing is just to uninstall all versions of Java you have, then reinstall it again - but download the offline installer instead of using the automatic online one.

Uninstall instructions here (including a link to Windows Installer Cleanup if you need it):

http://java.com/en/download/help/uninstall_java.xml

Manual download and installation instructions here:

http://www.java.com/en/download/help/windows_manual_download.xml