ITunes not responding to iPhone 5?

When I plug it in the laptop, iTunes doesn't respond but my computer does.a file will pop up called 'Apple iPhone' and have options like 'open files to view pictures' or whatever.
before this happened I had restored that iPhone with a backup made on my old phone which is an iPhone 4. That was done on a different computer (which might be the problem here).
I realized that and tried to restore the iPhone 5 settings again before plugging in into my laptop.still, same thing. No response from iTunes, just the computer.
iTunes will respond only to the iPhone 4. How can I fix this! Is it the phone that's the problem or is it the iTunes in itself?

It's a virus

Probably not a virus, as suggested by the previous answer.

iPhone and iTunes only allow you to sync to one computer. You're able to have playback of music from another computer, but you won't be able to make any kind of changes.

If you want to have the computer recognize the iPhone as a device that you can add music, apps, etc.to, you'll need to restore the device on the computer of our choosing. Remember, though, restoring and changing what computer your phone syncs to will remove All of the data on the phone, including images and music. You can get a lot of this back with iCloud backups, but be wary.