It's a pretty old machine - an Inspiron 6000 and I'm running XP. There isn't a battery icon on the task bar. Now it looks like the battery is fully charged. I haven't used it in a while, so it needed to be charged. I don't know that this battery has ever been in the machine for very long since it's the one that came with it and I bought one with a longer life (that's the one that probably died today) and used this one as a back up. It's been in a drawer for at least a few years.
I would just leave the battery out, since it's rare for me to NOT have it plugged in, but I have cats. Sometimes, they pull the cord out of the machine and, without a battery, that's not good.
Honestly, this computer is so old, that I probably won't spend any more money on it. If it needs more work or parts, I'll probably just scrap it, go back to using my desk top and wait until I have enough to buy a new laptop.