Iphone won't sync with Itunes?

I got a new laptop and set it all up with itunes and all that jazz but everytime I try to sync my iphone with the new itunes library it says not enough space the option for replacing new library with old doesn't even pop up. What should I do?

Added (1). And the new library doesn't even have as much music as the old one and it all fit still.

Hit control alt delete go to task manager then processes tab.end apple mobile device support and all iTunes and apple processes then re open iTunes and sync.