Browser not connecting

Hi,
I'm absolutely useless when it comes to technical computer-like things, but i really need some help! My laptop will show that it is connected to the internet but when i open a browser it says unable to connect.. this started a while ago and at first it was firefox that went down, but after a couple of days the same thing happened to IE. Limewire will still connect, and although msn doesn't when i click the troubleshoot button it doesn't come up with any faults, but the browsers just wont work. It happens with both wireless and wired connections. I've run several virus scans but they've come up with nothing.
Is there anyone who can help?!
thanks you in advance