No input or output

Started Cubase this morning and have no output from any track. On pressing play the transport line starts moving but no sound. Checked the vst connections, devices, inputs and outputs etc nothing changed. I record and playback acoustic instruments through M Audio fastrack. Device set-up: M Audio USB 2.0 ASIO. All looks fine, the thing is there’s no visual output from any track showing on the mixer panel. This I think is the heart of the problem, it’s possible that I’ve checked or unchecked a box somewhere and this has disabled all input and output. I’ve opened up several other projects and exactly the same, no sound no output of any kind. Never had this problem before. I’ve also tried recording but same problem. Checked the audio folders and all tracks are still there and will play quite happily in windows media player.
Windows 7 64 bit, Cubase 4,

Check the outputs for all individual tracks.

Thanks mashedmitten. Just tried outputing through the computer’s own ASIO driver again, this time it worked. All tracks outputting OK. Still no output or input from M audio drivers. So it looks like an M audio or USB connection problem, not Cubase.

Faulty USB cable.