MIDI connectivity issue..

Hi,
I wish someone could help…
My setup is cubase 5 win 7 64 bit TC electronic Twin Impact.
I have an arturia midi keyboard (analog factory experience) which worked fine until recently. Everything is properly connected and when I press a key I see midi in signal on the transport panel but not on the vst. Somehow the signal stops before it reaches the desired vst. I have tried re-installing the drivers of keyboard.
Any ideas?
Thanx