I have the same issue as the one mentioned on this page and have tried the solutions, but they have not worked for me.
Doublechecking something. Are there any LSPs appearing in the Winsock tab of Autoruns? If so, what are their names?
The symptoms still suggest LSP trouble, so it's possible we're looking at damage to the key(s) rather than a conflict here. If that's what is afoot, we might be able to clear the key(s) manually.
Doublechecking. Have you tried wiclee's instructions from the following post?
Can you check something for me please? I'd like to try doing a "Run as administrator" on your iTunes.
Quit iTunes first.
In Computer, open Local Disk C: or whichever drive you have your program files installed on.
If you have a 32-bit Windows, open the "Program files" folder.
If you have a 64-bit Windows, open the "Program Files (x86)" folder.
Open the "iTunes" folder.
Right-click on the iTunes.exe file and select "run as administrator".
Can you access the Store now?
(Permissions issues can sometimes mimic other problems ... if that's what is going on, the "Run as administrator" thing can sometimes get past the issue.)