TOYOTA COROLLA 01 - CHECK ENGINE & AIR BAG LIGHTS !

im currently driving a toyota corolla LE 01. for some reason now I have a check engine light and air bag light on. I have disconnected the battery and the check engine light will go off for a few hours then come back on, and the air bag light is now always on. how can i fix this ? with out having the hassle of the dealer ship ?! thank you...