Louisa, there are various possible reasons you're seeing this message. One could be that the site you are looking for is not responding. I'm not being sarcastic, but if there is a problem with one particular site you will get this message. If you are getting the message while you try to access several different sites then the problem could either be with your internet service provider, in which case you should check with them, they might even have a service status message on there own website, or it could be that there is a problem within your house. Is your modem switched on and plugged in and are all the cables connected? If you managed to isolate the problem to your own house, try switching off the modem for 5 minutes, then switch it back on and wait 3 or 4 minutes before trying to access the same sites as before. These suggestions will rule out most simple problems. I'm sure you will get more wise words from others.
Update, embarrassed, two seconds later. Of course as you have managed to post this message here the problem is not with your modem and you are not getting it with many different sites. It is quite possible that the server belonging to the website you are trying to access is either busy, down for maintenance, or otherwise not available. Try and get somebody else to try it or list the name here full stop
Martin
