Chains can be brokenmore than once... just not in the same place! Make sure when you break your chain that the pin you push out is not one of the replacement pins.
BUT! Do not break your chain to set limits - it is completely unnecessary and probable results in a less precisely adjusted system than if you were to have left the chain on!
Follow the instructions on the Park Tool website:
Rear Derailleur
Front Derailleur
If you follow all the steps therein and you are still ahving trouble, you may have a misalighned derailleur hanger or some other problem. Let us know how it goes!