When you click iTunes Store in the Source list, the main part of the iTunes window turns white and remains blank.
This happens if you are using Web accelerator software.
Solution
Download and install iTunes for Windows 4.2 or later.
Important: Information about products not manufactured by Apple is provided for information purposes only, and does not constitute Apple's recommendation or endorsement. Please contact the vendor for additional information.
Document 17159, "Locating Vendor Information" can help you search for a particular vendor's address and phone number.