if common sense (looking everywhere carefully) doesnt work - you could call in a security guard dog service - they have trained dogs that can sniff out where you hamster is and will not eat it when it finds it. If you ask a professional air conditioning or electrical company, they might come in you home and look for it with an infared (heat signature) camera and not charge you too much. PS - leave some little dishes of water and food all over, so when it comes out of hiding (probably at night while you sleep) it wont starve to death. hunting stores sell small animal traps that wont hurt it.