Itunes Store connection

Hello, I have recently bought a new computer and new Norton

 

I cannot access Itunes store, telling me:

 

"Make sure your connection is active"

 

I use T-Mobile usb stick and it worked on all previous computers - I believe it is just Norton and I wish I never got it now!!

 

I have tried to go on the firewall and allow and as far as I can see it allows it - I have added all the itunes icons I can see and I am becoming inpatient now! Any help? Step by Step even?

 

Thanks in advance