Thanks to all - I just discovered a film on the Tube by accident that I didn't realise someone had uploaded ... so I pressed play ... 2 hours 34 minutes later and not a hiccup. Yesterday I couldn't watch a video for 2 minutes.
To fair to myself, I did raise the issue of the power cut when it was fresh in my mind ... something like well over a week ago now - at another forum - they dismissed it and had me uninstalling and reinstalling Adobe Flash, that went on for days.
So apologies, if I'd come here first the issue would obviously have been dealt with successfully - I had almost given up on 'normal' online videos ... and I just watched a full length movie
Thanks again!