Thank you so much for responding. I'm going to try and test all that when I get home (at work now!).

for the ISP I live in the Cayman Islands so I'm not sure you would be able to know if it's the ISP that is affecting it. The firewall is just the standard Windows XP firewall.

Would you know why though why it has worked all this time and then suddenly it stops? We haven't changed any settings on the computer.

Thanks
Rebecca