Hi trunzo,
You need to be aware of a couple of issues with PowerBooks.
1) The plug connection (where you plug into the laptop) attaches to the Audio card. This is a point of frequent physical connection failure, either due to abuse or even significant normal wear & tear. It continued being a problem until Apple came out with the MagSafe connector on the Intel MacBooks. If this is bad, you won't be able to charge your battery, so this will need to be determined first.
If you're lucky, you might try plugging it in and _gently_ applying gentle lateral pressure on the plug - - you might be able to _temporarily_ get a connection (the plug should light-up and your battery (if present) should charge. I've been able to get this to work if the break in the sound card isn't too serious, but eventually, this won't work anymore.
2) These computers are now getting to be 8-11 years old. In computer terms, this is advanced old-age, well beyond retirement. While I personally liked the modular design of these computers (I own 4 Wallstreets, all but one are for parts), I wouldn't consider putting a lot of money into these unless I was going to use them as an old-fashioned case for new internal electronics - - for example, dropping in a motherboard/RAM/CPU from a newer MacBook Pro. (The real killer would be replacing the display - _major_ technical challenge there. And there we're talking a _lot_ of money and lots and lots of spare time to do the engineering. Unless you're doing it for a hobby, its not worth it.) Trying to restore one of these to working condition is going to be a challenge in just finding parts or a battery that isn't completely played-out.
If you want to explore this further as a DIY (Do It yourself) project, I highly recommend iFixit.com as a good source for both how-to guides and replacement parts. The URL for the Mac how-to guides is
http://www.ifixit.com/Guide/MacIf I can be of further assistance, let me know. If this helps or solves the issue, please rate it accordingly.
Thanks in-advance for using Fixya.com,
Jon