Vince, same thing happened with me since last 2-3 weeks. i finally formatted my pc last weekend and everything is back to normal.. there are some viruses/spywares which doesnt alow to open those websites...
It happened on XP and on vista (Dualboot) every site opened fast...
so i suggest u to format ur PC or get all viruses off ur system. even spyware cleaning didnt help me.. i also posted about this problem on te last month.