Breathing new life in laptop batteries

Hi, Thanks for all the info. Apparently there are no reliable way to bring their youth back, I would like to have a reliable laptop with a battery that last more than 30 min. I found a Zenith z-star 433 VLp (500 Mb hd, 12 M RAM and color display and the Zenith J-Mouse!!!) that I'd like to use while away contacts does this means that it provide mutiple voltages or is there some kind of charge sense signal? I haven't brought the battery to the bench yet (no room on or near the bench:). Also the pack seems to be sealed pretty good, any elegant way to open it up and reclose it without too much damage? Thanks Francois PS: I actually got 3 of these laptops and built two from the set of parts and two of the batteries are totally shot: they get very hot when I try to charge them and of course no juice is coming out. I can practice on one of the dead ones. will have