If you can connect to MSN, you have connected to the Internet.
Which bit of Talktalk broadband can you not connect to?
Open a command window - click Start- Run and write CMD in the box and hit "Enter".
In the black box that appears, type ipconfig /all
You will get a screenful of information.
In there will be an IP address, Default Gateway, and DHCP Server address (or should be, anyway).
Post those in here, and we can tell you what's up.
Edit: the 192.168... may be 10.0.... That's fine. If it starts 154 or similar, there's a problem.
If the IP address starts 192.168. then you are connected to something. Type ping bbc.co.uk and see if you get a response from the BBC. If you do, your Internet connection is up and working. The problem lies somewhere else.
Edit: the 192.168.. may be 10.0... That's OK too.
If it starts 154 or similar, there's a problem.