Could someone PLEASE explain what is going on here?
'It is possible that your system's hardware has changed'
I now have to reconfirm the licence.
This is a laptop - the hardware hasn't changed at all because it really cannot change!
This is the second time this error has come up in a week. What on earth is going on? 
what if you start the program as administrator?
I haven't tried that - mostly because if you do (as my other post says) you cannot drag and drop audio files into a new track.
Why does this feel like I am beta testing someone's software, despite having paid good money for it?
...and now it has decided to start working again. The only difference is that I am now at home and not on a train.
What hardware is it checking? This is crazy!