Are you installing the 64 bit or the 32 bit Java? Firefox only works with 32 bit java. http://ninite.com/java/ninite.exe will give you both installers (make sure Firefox is closed first)

If Firefox doesn't find the Java plugin then it is possible that the Java installed didn't create the required registry key that Firefox checks to scan for plugins. 32 bit Windows:

• HKLM\Software\MozillaPlugins\@java.com/JavaPlugin,version=10.xx.xx

64 bit Windows:

• HKLM\Software\Wow6432Node\MozillaPlugins\@java.com/JavaPlugin,version=10.xx.xx

See also:

• http://kb.mozillazine.org/Java
• /questions/937263

Yep. Installed/Reinstalled both 64-bit and 32-bit versions. Both work with 64-bit and 32-bit Internet Explorer but not on Firefox (32-bit only, of course).

Do you recommend me make my own registry key then? will it cause any issue upon updating, reinstalling, or uninstalling Java in the future?