iphone 4s wont connect to pc

everytime i connect my iphone 4s to my pc it starts vibrating constantly and my pc keeps replaying the sound of a connection being made over and over again. the battery on the phone shows charging and then normal and keeps flicking back and forth every second. this leads me to believe that the connection is being made and then lost and reconnect etc. ive tried stopping the apple mobile device from the admin tools and restarting it but still the same issue.

i have windows 7 ultimate.

any help is appreciated thanks.