iBook will not turn on!

[Roy & Brendon]

I'm having trouble with a 500 iBook (late 2001) not recognizing the 
power adapter. The battery is dead and when charged only holds about 20 
mins. The adapter is working, I've tried it with a 14" ibook. i've 
reset the power manager a couple of times as per Article Id: 58385 on 
Apple's support pages, but no luck -

Can anybody suggest what the problem may be, or is it a trip to the 
Apple repair shop?

Thanks in advance

Roy