I was looking through our resources to see what I can find on the issue you're experiencing and think that I have found the perfect article. It's called Trouble installing iTunes or QuickTime for Windows found here: http://support.apple.com/kb/ht1926
I know that you have re installed iTunes already, but sometimes reinstalling just iTunes does not help some related components like Bonjour, unless you remove them from the system completely, then re install.
The steps to do this are toward the middle under General Troubleshooting.
General installation troubleshooting