Close your iTunes,
Go to command Prompt -
(Win 7/Vista) - START/ALL PROGRAMS/ACCESSORIES, right mouse click "Command Prompt", choose "Run as Administrator".
(Win XP SP2 n above) - START/ALL PROGRAMS/ACCESSORIES/Command Prompt
In the "Command Prompt" screen, type in
netsh winsock reset
Hit "ENTER" key
Restart your computer.
If you do get a prompt after restart windows to remap LSP, just click NO.
Now launch your iTunes and see if it is working now.
If you are still having these type of problems after trying the winsock reset, refer to this article to identify which software in your system is inserting LSP:
iTunes 10.5 for Windows: May see performance issues and blank iTunes Store
I'm having this same exact issue. I use a Macbook, and iTunes works just fine. But whenever I attempt to open the iTunes store, it loads about halfway, stops loading, the loading bar turns into the apple logo, and iTunes store is just a blank screen. I've been searching everywhere for the solution for this issue, and all of the results i'm getting are for Windows. I'm sick of it and all I want to do is access the iTunes store.