Have a nice digital camera bought around December?

- been malfunctioning a bit- mostly as when press shutter button everything seems to be right except no photo is taken. Also flash not going up. I'm worried it's damaged (teenager used on vacation) but is there good possibility battery is shot? I charged it and can't really figure if low charge only causing problems?

is it common that dig. Can needs new battery? Is Nikon 8100.

Please start by studying the manual.

Everything you mentioned could very easily be caused by user error, and if you knew how to use it correctly it would work just fine.

Start with the manual, then if you still think it could be a battery issue:
Rechargeable batteries have a life span.
There comes a time where they simply don't recharge anymore.

I'll cross fingers for you that all your camera needs is some brand new batteries.

Sometimes, it can even be something as simple as dirty contacts - use some rubbing alcohol to clean all the contacts and let them dry for a minute before you put the batteries back in.