1998 Honda Civic Engine Light On

Thanks for your help. My 1998 Honda Civic, very low mileage, 25000, was not used for the last 9 months, friend had battery changed 9 months ago. The check engine light came on now. I am not sure if they messed up something while changing the battery. I am not inclined to go to D(St)ealership for fear of wasting money. Can i just reset the light somehow? Could there be any other problems. It was running fine 9 months ago before i parked it in the Garage. I appreciate your time.

Thanks,
Satish