Can't use installed input language?!?

I installed Hebrew as an input language back on Windows XP Pro SP2. I
upgraded to Vista Ultimate and Hebrew still worked for a few days, then it
took the language bar off of the taskbar and it doesn't show up on the
toolbars menu. Now I can't even switch languages so I can't use Hebrew. I can
see the settings for the language bar in the regional and language options,
but i can change them. I can see Hebrew installed there too but I still can't
use it. What's up here and how can I fix it?!?!!