Won't charge I plug it in but won't charge

First, I would check your batteries. Start by removing them and making sure that the battery contacts in the camera and on the batteries are clean. If they are dirty. A new pencil eraser can be rubbed against the contacts to remove any oils or residue. Next, I would make sure your batteries are charged. Since you did not state which model Coolpix camera you have, I do not know if your camera uses AA batteries or a battery pack. If it uses AA batteries, a quick way is to check is to take them out and put them in another device that takes two AA batteries and see if it works. If the batteries are bad, put two new alkaline (non-rechargeable) batteries in your camera to see if it powers up. If it does and you wish to use those batteries, be sure to go into your menu and set the camera to use alkaline batteries because there voltage output is slightly different from rechargeable batteries . Remember that you cannot recharge those batteries and trying to do so can damage your charger and cause the batteries to explode. If your camera uses a battery pack, I would buy an external charger from Nikon. They are inexpensive and if it turns out that the charging circuit in you camera is defective, it will save you a repair bill by providing you with an alternative means for charging your batteries. If the camera will not power up with new batteries, the camera will need to be sent in to Nikon USA for repair (see the Nikon website for information). If the camera powers up with the substitute batteries, either your rechargeable batteries have gone bad or you camera's battery charger is defective. For problems with the internal charger, it is probably more cost effective to buy an external battery charger then to send the camera in for repair unless your camera is still under warranty. External battery chargers are available for under $20. There is one other possible cause of battery failure. If the camera's internal circuitry has an electrical problem, especially a short circuit, the camera will draw excessive current from the batteries and run them down. If that is the case, you would obviously need to send your camera in for repair.