Several years ago, I purchased a Dell Latitude D600 -laptop (used- from an online dealer). ---No complaints--it works great! ---I most often use the AC power source--- ocasionally, I use the battery as a power source (i.e., without the AC adapter pluged in). Recently, my computer consultant (I am not great with computers), told me that my battery is not holding the charge--- and, I need a new battery. Anyone, suggest where I should buy a battery (e.g., on line)? --and what model of battery? --- Are there several online sources that you know to be reputable? --- I guess I could contact Dell and ask them--- but, I just, now, registered with computerforum.com, and I thought I would give the forum a try ---I thought someone in cyberspace could give me some good advice. ---Thanks for any help, Jaes.