If you've ever loaded up your iTunes and it gets stuck on "Accessing iTunes Store" then you can feel the frustration of just waiting for it to complete but it just stays on the message and only goes away when you click the little "X"
If de-authorizing, repairing, re-installing the program does not solve the problem then try this:
on a Windows machine go to the START button, the search box type, "CMD" which will find the cmd.exe but don't press enter. Right-click and click "RUN AS ADMINISTRATOR." At the command prompt, Type "NETSH WINSOCK RESET"
You will need to re-start your computer after that but should be okay.