get message from iTunes and Skype saying "must be connected to internet", to open/download when I am really on-line and am connected??

Hello,

I have a Dell Deminsions 550.

I have been getting messages from Skype, and iTunes that they cannot download updates, because I do not have an internet connection, and that "Skype is not connected to the internet, when I am on-line. I also cannot open Norton Anti-Virus, but my computer control panel shows I am protected and that it is running.

I had to reconnect to my Wi-Fi internet server because the old one ceased to function and my neighbor, whose server it is, got a new server.  I was trying to connect to the new server  through my computer's software, but my connection is via a Belkin USB connector, and when I changed to using the Belkin USB connector, I got on line easily. I wonder if some programs are trying to connect through a program my computer was trying to run and cannot.

I also, some time ago, had some computer problems and the tech I contacted fixed it by splitting my C drive in some way, and I also wonder if the problem is that.

Also, Skype couldn't access my remote access for repairs.

I  can swwitch logged in users, although my control panel shows only one identified user. And, I know I am switching users because I can update my Acrobat flash player only on one of the logged in useres and not the other. Skype,and  iTunes, wont update on either of the "users". Norton does not show up on either. Both say "my name Admin" and both have the same picture.

Any suggestions would be very much appreciated.

Thank you,

Nanc 223