I have experienced problems with Dell power adapters where the power pack will not charge the battery even though the battery is good. I do not know if Sony power packs have the same problem. On my dell, you can go into bios and it will tell you what AC adapter you are using (60 watt or 90 watt). If the power pack is bad, it will say unknown. You may want to check you bios and see if it has anything similar to this. If it is the power pack, it may save you on buying a new battery. My laptop would still run on AC even though it did not charge the battery, so do not assume that just because the laptop runs with the power pack, that the power pack is not the problem.
