Yep, the driver had gone. My fault. But then I became concerned that I'd not written a word of my book today and took the coward's way out. I did a system restore.
All working - but the Skype logo on the task bar was still not there. Odd that.
As one who Hibernates most nights, the reboots, I thought, might just have kicked things back into life, given W7's propensity for finding drivers. I thought it might just do the trick. But can't win em all.
Anyway, one thing learned. Skype drops it's input source should it disappear for a moment.
It would have been nice to know just what occurred.