Cannot switch on multi effect pedal

Hey friends i own a zoom g2 multi effect pedal which isn't a very high quality one but it was only one i could afford back a few years ago. Anwes the thingis i haven't been using it for a very long time and now that i try to use it i cannot switch it on. It can be use with 4 aa size batteries or through a dc adapter but i tried both and still it's cold dead. Can anyone tell me what is the fault in it?