Videos Not Playing?

[jroug]

Strangely no online videos (YouTune, Vimeo, Hulu, etc) are playing on my Mac Pro - in fact many not even displaying on sites they are embedded on. Videos in my iTunes library are fine though, so guessing it's not a graphics card issue but a safari setting? Any thoughts? Thanks in advance!

 

[derbothaus]

Install Flash.

 

[jroug]

Yeah, that was it. I feel stupid but didn't consider it as it was running with no issue. Now, after reinstalling, it is gone again. Can't figure out why, any thoughts?

 

[derbothaus]

Maybe permissions? Safari>Help>Installed Plug-ins. Is it listed?
HD/Library/Internet Plug-ins. Is it there?
Does it work in Firefox or Chrome or Opera?
Do you have extensions that could be blocking it?