iBook - Is it my battery or my motherboard?

Hello all!

After losing data due to broken windows for the last time, I upgraded to a mac.
Man I love this thing, but I'm having a problem. Every time I start it the date and time are not set. After doing a little googling I found out that my PRAM battery is bad. This makes perfect sense because in addition to the date and time I HAVE NO BATTERY!!!!!

So I guess my question is can a working battery that held about a 2 hour charge go bad with no warning? It seems a little loose even when locked in, but it always has. I found a replacement on ebay, but if there is something else that may be wrong why spend the money for nothing right.

Here is my system profile,

Hardware Overview:

Machine Model: iBook
CPU Type: PowerPC 750 (2.3)
Number Of CPUs: 1
CPU Speed: 900 MHz
L2 Cache (per CPU): 512 KB
Memory: 640 MB
Bus Speed: 100 MHz
Boot ROM Version: 4.6.4f1
Serial Number: RM409ZBGPBN
Sales Order Number: F9009LL/A


If anyone knows what the problem is, or a way to trouble shoot please let me know :-)