Itunes won't sync music onto my iphone 4s?

Ok so i have an iphone 4s and i have music on my hp laptop in itunes.music from itunes won't sync onto my phone and i don't know why? Apps sync and stuff but music won't sync… Why? I really need help! Does anyone know why this is happening or how i can make it work again?

If you look on the music tab under Summary, it will show all in grey until you check the top box that says "sync music".
You can then chose your library, playlist etc.

apply
Sync
That should do it.

  • Why won't itunes sync my CD onto my iphone? I brought two albums and put them on my itunes but when I plug my iphone into my laptop the two albums won't go on to my phone? Why is it doing this and how can I make it work? Its been frustrating me for months! Also before when I had a blackberry ages ago I put videos up from when I went to see lady gaga on my laptop, can I put those videos onto my iphone to?
  • Why won't my iTunes sync my music onto my iPhone? When I plug my iPhone into my laptop and open iTunes to sync my music, it starts to back up all my things onto my computer but it never actually goes passed the backing up, it just stays on that. I've left my phone being plugged into the laptop for over 2 hours and when I returned it said it was still backing up. I want my music on my phone but I don't know why it won't work, help?
  • Why won't my Amazon MP3's sync onto iTunes? I downloaded two albums today from Amazon.co.uk via the usual Amazon mp3 downloader. But, when I open iTunes and sync my iPhone, the albums do not automatically appear as normal. Yet, the files for the downloaded albums are in the iTunes folder in 'My Music'.
  • Why does iTunes need internet access to sync music CDs onto my library? I noticed my internet went out and while syncing music cd's I noticed it didn't show the track names without internet out of curiosity I'm wondering why it needs access to syncing cd's onto my iTunes?