I had the same issue as described above... iTunes would crash everytime I tried to open the iTunes Store. My brother, a computer geek, had me do the following and it fixed the problem for me:
1. From your desktop, right-click "My Computer" and click "Properties" (If you don't have the "My Computer" icon on your desktop, use the following steps, 0.1 - 0.5)
0.1 - Click the Start Menu button (Or use the Windows button on your keyboard)
0.2 - Locate "Computer" (should be in the right panel near the middle)
0.3 - Right-click on "Computer"
0.4 - Click "Properties" from the option pane
0.5 - This should have opened the "System" window (in the control panel also), continue to step 2
2. In the "System" window, click on "Advanced system settings", this brings up the "System Properties" window
3. In the "System Properties" window, click on the "Advanced" tab
4. In the "Advanced tab", click the "Environment Variables" button
5. In the "Environment Variables window", find and highlight the "Path" variable in the "Systems Variables" section
6. Click the "Edit" button to bring up the "Edit System Variable" window.
7. Finally, place your mouse cursor at the very end of the "Variable Value", and modify the variable value by adding the following (EXACTLY) to the end:
;C:\program files (x86)\common files\apple\apple application support\
