I have already recovered some notebook batteries, a tip I can give you: Open the battery, release the cells, measure each one with a multimeter, if you notice that all are + or- 3v, but one or the other is 0v, it can be that those with 0v have opened an internal protection fuse. Since the battery is connected in series, if one fails, the entire battery will not work. You replace only the damaged cell. A tip (do it at your own risk): If you attach the battery to a vise, and press the positive pole a little bit inwards, you will be circumventing the cell fuse, and it will work again. Of course not for the notebook, but you can use it to use elsewhere, such as a flashlight.