Sorry to bounce the thread but I thought an update to other newbies may be of use.

Have since down loaded the odd film and indeed did get the "codecs" error.

Followed your top advice and opened said file up with VLC player and everything runs like a dream.

So a big thanks for the most excellent advice and to any newbies, do a search first to see if you can suss out your problem, then if no joy, get the guys on here to lend a hand. They know their stuff.