Bought a laptop and cannot get security code for internet

[Simonswain]

Hello,
I have just bought a Lenovo Z570 laptop. I have a desktop and wireless internet with Talktalk.
I have no idea what my original security code was - how do I find it.
I am also a complete laptop novice and this is probably a very stupid question but what was the dongle thing that currys tried to sell me. I did not buy it as I had no idea what it was

 

[Saga Lout]

Answered in your other thread.