You must be in the wrong place. iDog tech support can be found
here.
First, batteries in the iPod are not user replaceable. If you figure out a way to open the iPod your sister's warranty will be void.
Second, the iPod has no power down sequence. In fact, the user cannot turn it off at all - all we can do is put it to sleep. After about 14 hours of sleep the iPod will automatically put itself into hibernation.
Third, iPods don't generally turn on for no reason at all. I can think of two logical reasons for this. First, when the iPod is asleep you can wake it by touching the click wheel. This is normal and, this is why there is a hold button on the top of the iPod. (Hold is engaged when you see orange on the button) Second, your sister may have inadvertently turned on an alarm.
Since neither you nor your sister seem to know much about the iPod, I strongly urge you to read the manual. It can be found on the CD - it is a PDF file. Also, you might find this
site useful.