Phone is not turning on

I charge my iphone 32gb 3gs and when iam trying to charge it,it turn off and turn on again anf show the apple logo and turn off.and I can never turn it on .due to my busy sched I just used my spare phone and kept in storage the iphone.aftr maybe 1 to 2 yrs I need someto files that is installed in my iphone.so iI decided to charge it but its not working.Ive read one of the post here that is similr with my prob to blow dry the phone and charge it.I already tried to blow dry it for more than 10mins but nothing happen.i clean the socket charge in the phone.bought a new charger but still nothing happens.It seems that my phone is so drained and I dont know what to do.I know its a old version of iphone but I need some files that is not save in in my icloud accnt.I hope someone can help me.is my batterydefective is already broken or what should I do.thanks in advance