Iphone4 Wont sync with itunes

[gavinlee77]

My iPhone 4 will not sync with iTunes since I updated to iTunes 10.4 it knows that it's my phone but just won't sync and now says to restore I've deleted then reinstalled iTunes but still no joy My girlfriends one still syncs fine..

 

[bab2010]

Reboot your iPhone or hard reset it and try to sync afterward.

 

[gavinlee77]

Hard reset as in hold home and sleep button??

 

[gavinlee77]

What does hard reset do??