I highly doubt your Box issue has anything to do with
Java Deployment Toolkit. It's more than likely to be something in your profile, which more of the time has to do with add-ons. You can try Firefox Portable, and go on Box to verify.
To fix, first try deleting all of you history, cache, and other settings (after backup if you want). Then try Firefox Safe Mode with all add-ons disabled, or even everything reset. If problem goes away troubleshoot (selectively enable) from there. If not, you might need to re-install Firefox (you can still keep your profile).