Problems watching You Tube video's etc

Hi everyone. This is actually a problem that my son is having on his laptop. He was previously able to watch You Tube video's and also to sign onto our TV channel web pages and watch catch up TV programs that he had missed on TV.  He thinks the problems started when he downloaded the latest version of Flash Player but really isn't sure. Neither of us is tech savvy, I'm 60 years old so I will need precise instructions in layman speak thanks.  I did check his settings against mine and they seem the same.  I also un installed and re installed Flash Player.  But he is still is unable to watch videos. Any suggestions.

Thanks Buddie