Can't view videos on some sites

Hello there, newbie here!

 

I'm having trouble with some websites namely youtube, five.tv/demand five, channel4 etc (UK) when viewing video clips programs.

The website says that I either have Javascript turned off or need to update my flash player.

 

I have Javascript on and the latest flash but still it tells me otherwise. I've removed previous versions and reinstalled but to no avail. However when I disable NIS and reload the web page - HEY PRESTO video works fine - then I re-enable NIS and things work fine until I close the page and open another one.

 

I have NIS 2005 Anti VIrus Ed. installed fully updated. I'm running IE8 (does the same with Firefox too)

 

Please if someone can point me in the right direction I'd be grateful

I've had a quick search of the forum but coudnt find anything so apologies if its already been solved/commented upon elsewhere. Feel free to move this post too if need be.

 

Thank You

Scott