Hi Penny,
I had a Ford Escort and the very same problem happened. I had it checked out by a Ford main dealer and the reason was as follows. The airbags are activated by impact and by a hard pull on the seatbelts. Somewhere under the front seats where the seat belts are fixed, there is a part that activates the airbags. This part needed to be adjusted / replaced. But the cost of removing the seats and replacing the part was high. It wasnt that the airbags wouldnt work in the even of an impact, it was just that they may not be as sensitive and work in the event of a smaller impact. During the car service, they reset the warning light but it came back on about 3 months later. They did the same at the next service. Hope this helps.