Any help! Problems with my Internet Connection?

Our Internet access is very Intermittent! When we try to go online, sometimes the 2 little monitor symbols on the task bar (which indicate internet connection) do not have the small globe symbol, and just shows a yellow triangle symbol! This has been going on for about a week now, and we've never had a problem before! we are using Vista and the funny thing is that my parents are having exactly the same problem! We both receive our broadband from Orange UK. we rang them and they said to reset our Internet Explorer settings! this worked for a few hours, but began having problems again. any help would be appreciated x