No sound on iPlayer or You Tube

[objectivity]

For some reason whenever I play anything on either of the above the item plays but without sound. On You Tube I have to download the file and then it plays on my laptop (vista) through Real Player or other program complete with sound.

Any ideas why I'm not getting sound direct through these sites?I'm using Firefox.

I had this problem. You need to download the latest version of something. think it's flash but will check and post in minute

Macromedia Flash.

Thank you sarahsails

Did it work?