New itunes won't sync music correctly?

I downloaded the latest version of itunes and i see a lot has changed with appearance. Anyways I have a iphone 3g that i use as my ipod, and have never had problems syncing music too. When i clicked sync on the new itunes it says that it is syncing but when i check my iphone, the newer songs aren;t on there. Then i deleted some songs but when I synced they were still on the iphone after the sync. I don't understand why this is happening can someone please help me out?

First of all, do you have the latest version of itunes as 2 were released very close together:

1.0 December

11.0.1 December 16th

First of all I would completely uninstall the version you have, this will not affect your music and media files:

Now download the latest version direct from the Apple Site:

http://www.apple.com/.../download/

Restart your PC after installing

Open itunes:

you will see a small black and square icon to the top left of your screen
click on the icon
click show menu bar
click view
click show side bar

Now try connect your iphone to itunes via USB

You should now see your iphone listed in the left side bar under 'devices'

click on it and try to synchronize from here.

I hope this assists you in resolving your issue, it worked for me when 11.0 would not work correctly.