[osterly1]

hi there i keep getting this message popping up when i try to go to some web pages, story goes that some pages i can goto , then when i try to goto difefrent pages i get this message if i go back to the page i wass on its ok and works, its not juyst 1 site that i get this message but a whole host of them , like yahoo ebay , some flash poker sites , none of which will lad or if they do , then the pictures will be missing and just displayed as a small red x, then i goto car forum and it will work fine, then after a few hrs the thing seems to repair itself, then afetr a few hrs it happens again, then fixes again. this has been going on for nearly a week now and begining to piss me off somewhat now, so can some1 advise me how to fix , many thks