Wont play any videos

[Fawkes]

Im new. I bought a new iMAC 27". Im wery satisfyed with it, but one problem has emerged.

Suddenly over night it wont play any online videos. On youtube the videoscreen is completely black and doesnt start. Not any of the other videoservices either.

Internal videos like tutorials works fine, but not the online ones.

Im clueless. Please, anyone?

 

[Fawkes]

Works fine in firefox but not safari.

 

[John Doe 57]

Are you using the latest version of Safari?

I'm thinking that this issue has something to do with the Adobe Flash plugin.