Hi depending on where you bought it the coin mech might be unplugged (hence why you cant see any light) I know to sell fruit machines on ebay you have to disable the coin mech but other than that do as bas sugested and clean inside that flap that opens out when you press the eject coin button on the mech
have you got your password stored in msn? sometimes my msn says invalid password so I uncheck the save password box and type it in again and it works then...dunno why it does that