Vannot Connect to the Internet

I have just restored a laptop computer (Advent) to its "factory settings". However, I cannot connect it to the Internet. There is a button on the laptop to switch wireless on and off. It is switched on. I have connected it to the Internet using a wireless router. I know that the router is working as I've connected to the internet via the same router to send this post on a different computer. The icon in the taskbar says that the computer is connected to the Internet.

I've tried updating avast! and that updated so I suspect it is connected. The problem is with internet browsers. In Firefox (v. 12) it says: "The connection was reset. The connection to the server was reset while the page was loading."

In Internet Explorer it says: "Internet Explorer cannot display the webpage." It gives an option to "Diagnose Connection Problems" but it does not give any solutions.

The computer runs on Windows Vista.

 

I should have been more careful when I named this thread. Obviously, the first word should've been 'Cannot' rather than 'Vannot'.

Despite that carelessness, I've solved my own problem. It was a firewall that was preventing internet access.