Windows Live Messenger e Toolbar on Vista Businnes

Hello world,
i've tried to install Windows Live Messenger on Vista Bussines, but it
doesn't function correctly. The installation goal is good, but when i launch
the application, it doesn't start. Not appear nothing near to clock (in
traybar), not appear any window. In the taskmanager the process is in list
and i can only terminate it.

How i can solve?

Thanks
--
Force and honor!!!