Alright, completely uninstall the version you have of iTunes have. Go to control Panel and go to " Programs and Features", then scroll down to iTunes in the programs list and uninstall it.
Then go to your "Computer" and go into your "C" Drive and go to the programs folder and delete your iTunes folder and then go back to "My Computer" and go into your C drive again and then go into "Documents and Settings" and click User and then go to App Data folder, or Application Data( you might have to go through a folder called "local" to get to app data, maybe) and if you see an ITunes folder in there.. Then delete it.
After ITunes is completely deleted, go and download the Newest ITunes and reinstall it again and try it. If it doesn't work then it would be on the Computer side and then we can troubleshoot from there.
Please reply telling me if you need help with anything I just said, or if it did not fix your issue.
Sorry if I didn't explain well enough, in school. Let me know if you need help with it.