Hello. I'm experimenting troubles with certain sites like Youtube, Hotmail or Twitter. I receive a message from Youtube like "You're using an obsolete browser", but I have the latest version of Firefox. I've tried re-installing and re-updating but nothing changes. Also I can't read my mail in Hotmail because I can't "click" in some links like "Inbox". On Twitter I'm redirected to mobile version site but I'm operating from a desktop pc and I read this message on the top of the page: "You are on Twitter Mobile because you are using Internet Explorer 6" but, of course, I'm using latest version of Firefox. Thank you.