After updating my iPhone 4 to ios5 music from my playlist won't play?

Question

After I updated my iPhone I try playing music and only the songs that I bought on iTunes will play on the iPhone, when I click play nothing happens. The songs will play fine on my computer. I resented and hard reset it sinc it twice and still won't work

Answer 1

I tried all the things in the forums and I also did all the things the Apple techs told me to do...  Uninstalled iTunes completely, and then reinstalled.  I erased all the info on my iPhone 4S, set it up as a new phone and tried to sync again.  All of it failed to work. 
Here is what worked for me:
1) Start iTunes
2) Connect iPhone
3) Click on iPhone device in left hand column
4) On the Summary tab, in the Options section, I had nothing checked.
5) Check "Convert higher bit rate songs to 128 kbps AAC"
6) Started sync
7) Waited until a track was syncing
8) Uncheck "Convert higher bit rate songs to 128 kbps AAC"
9) Click on Apply and started the sync again
Most of the tracks made it over but not all of them. 
I sent my computer and iTunes diagnostic information over to Apple and now I'm waiting on a response from them on how to get the remaining tracks over to my iPhone.