New laptop but I can't sync iPhone?

I recently got a new laptop for university. I've just been trying to remove my apps via iTunes on my new laptop but a notice pops up saying that my iPhone is synced to a different laptop (my old one). I've tried so many forums to help me but nothing is working. I'd just like to remove the memory on my old laptop so I can sync my iPhone to my new laptop - any help?

Initially import all your itunes songs from the old computer to the new. Both computers need to be connected on the same network either via Wi-Fi or ethernet. Make sure you have the latest versions of Itunes on your new computer, and log in and authorise your new computer (see below) with your itunes account

On both computers turn on "home sharing" (itunes, advanced, Turn on home sharing) on both itunes and choose import tunes on the new computer. All your tunes should be copied over. Do a final sync with your iphone on the old computer

Then deauthorise itunes account on your old computer

To authorize a computer to play iTunes Store purchases, choose Store > Authorize Computer.

To deauthorize a computer, choose Store > Deauthorize Computer.

After that your iPhone should sync
HTH
David