Norton Internet Security with Windows 7: no wifi connection

My brand new Samsung RC530 notebook with Windows 7 Home Premium and Norton Internet Security does not connect to my router Linksys Wireless-G WRT54GL.

My notebook is receiving my access points (and many others nearby...), but despite writing the CORRECT (copied from the router itself) password, no connection can be established.

Following some forums suggestions, I deactivated the Norton and Windows firewalls, but yet a connection is not possible.

 

Note: my router works perfectly with other laptops using Windows XP as well as with a web radio and even a Playstation 3.

Any kind suggestion?

 

My computer knowledge is quite limited and I run short of ideas.

Thanks in advance

Alberto