IPhone 4 battery completely dead?

I got an iPhone 4 from my friend and it's dead. Is it possible for it to be so dead that it won't even light up at all when I hold the power button? I'm about to get a charger soon, but I don't know if it will even charge. Basically, I just want to know if it just needs to be charged really badly.

Try charging it

Yes.

It most likely needs to be charged, but if it doesn't boot you'll most likely need to replace the battery. That's a very difficult thing to do in iPhone's, by the way! Gosh darn Apple and their stupid glue and soldered RAM and such