Ubuntu :: Adjusted Input Sound Volume And Maverick Lost The Plot?

I'm running Maverick on an HP dv6 laptop. I tried recording a video via VLC with the machine's 'TrueVision' webcam. The result seemed to lack audio, so I had a look in preferences > sound. The input tab had the mute button ticked, so I unticked it and tried adjusting the level (while realising I was probably just configuring the mic port and not the webcam's inbuilt mics).

Then things turned bad: pointer became sluggish, and changes I made to the level slider took ages to be reflected visually on screen. I queued up a pile of clicks on the 'close' button and went away for a while. On return, I was met with a box inviting me to stop a script with some screen-width-long incomprehensible name, which of course I did.

Now the system's in a state which sees windows missing title bars (tho' not menu bars) and (more problematically) the upper and lower bars on the desktop absent. I issued a hibernate command from the terminal in the hope that on waking the system would be 'fixed', but nothing changed. I tried alt-tabbing to access my open applications and close them gracefully but this command is ignored. I have 'zillions' of apps going with unsaved data and am not sure what to try next. I'd be happy just to be able to task switch to each open prog and exit it gracefully then restart. But my knowledge of the command line is such that your help is required =) .