If your msn, google, hotmail, yahoo everythings works but twitter pages not open, then I have to say why is it doing that and how can i fix it? Go to internet server, go to TOOLS, OPTIONS, PRIVACY TAB and in blue writing it will say you may want to CLEAR YOUR RECENT HISTORY or REMOVE ALL INDIVIDUAL COOKIES . Click REMOVE ALL INDIVIDUAL COOKIES and then when your done press OK button and go to the website. If nothing there maybe something wrong with the website provider so the website would be facing issues, someone may have blocked it like put parental control on you can unblock websites just type in google unblocking websites and many links should pop up. If not there could be something wrong with your pc. Twitter and all that could be overloaded with too many online or someone may have blocked out social networking sites because facebook and twitter are popular sites there could be a lot of people on at the same time and the websites can not run too much memory in their system that is why it might time you out. If that can not help you phone your internet provider and they will probably put you onto a technician incase your internet provider has run into doubts with these websites or is facing problems.
If that does not work take it a technician. That is all i can say you may find that a few methods may not help you but hey you looking for an answer i have a bunch of them and i am saying at least one should work why not try it. Best of Luck.