how can i fix my dewalt batteries?

First of all, go and see a DeWalt authorised repair agency .There is a good chance that the batteries might be replaced under guarantee if less than a year old.Failing that, it could be possible to get the repair agents to put your batteries in a special "conditioning charger" which could rejuvenate them.
Talk to DeWalt, they should be able to advise you.

Pete
March 2006