Please help.....I have a new I phone 4s, trying to sync with my I tunes on windows 7 (dell laptop) I have set up 'sync this device over wifi and its says its syncing but when it's finished it says ''no content' in music on I phone. Please help :-)

Please help.....I have a new I phone 4s, trying to sync with my I tunes on windows 7 (dell laptop) I have set up 'sync this device over wifi' on both the phone and in I tunes and its says its syncing but when it's finished it says ''no content' in music on I phone. So it hasn't synced at all! ive been in contact with someone from Apple via e mail but nothing they have suggested has mad any difference :-( Please help :-)