iTunes not responding

In the last 2 weeks iTunes takes 15 minutes with a box open stating its updating library. The it is Not responding and i have to force quit, completely unable to open it or use, at all.

Does anyone have a clue as to whats going on, Macbook soon to be going throw a window and under the wheels of a truck!

Apple seem to now have removed on line chat for this problem!

Help.

thanks

mark