DSL acting up

I am a beginner to computers and am having a problem with my Verizon DSL. It works fine on my default browser, Firefox, but won't work on Explorer, iTunes, or other online programs.

Windows firewall is what's running. I selected Explorer and iTunes on the exceptions tab and it still won't allow it. Here is the exact message I receive upon trying to open iTunes Music Store:

"iTunes could not connect to the music store. The network connection was refused. Make sure your network settings are correct and your network connection is active, then try again"

Please help, I really need it!!!

Do you have another firewall running perchance?

It could be that IE is configured for a different connection and Itunes piggiebacks off of the IE connection somehow. In IE go to Tools->Internet Options->Connections. You should be able to select never dial a connection.

How would I know if I have another firewall running? where could I check? And I tried changing IE's settings to never dial a connection - but it didn't work. Any other ideas?