I have seem similar post but could not find it after I registered for this forum. Besides mine is a Windows 7 Home premium 64 bit problem combined with Outlook 2007 and perhaps the Internet Explorer 9 beta. I can;t guaranteee it but I believe it happened after I installed the IE9 beta, but can't be sure. Anyway when I open Outlook 2007 and click on a you tube link, I get the message this operation chad to be canceled due to restrictions on this computer. Otherwise Outlook works fine. I can click on other attachments (.wmv and .pps) and everything is fine. I did a system restore but it could not complete. I sent the email to my Gmail and could open the link in both Chrome and Fox Fire. So it seems to be either an Outlook problem of IE 9. I tried to send a bug report to IE9 system but that is an abysmal mess __ can't do it unless you pretty well know what the problem is. So I hope somene here can help. I did do some Google searhces but most seem to focus on Vista or XP, not Windows 7. I do know that you tube requires flash and there is no flash available for 64 bit Windows 7.