2002 Honda Civic SRS light and Clicking sound for the engine

Car: 2002 Honda Civic LX
Milage: 74,000
Engine Size: 1.7 liter
Transmission: AT
Body: Sedan

Hi,
I have two problems with my 02 Civic that I would like to get some help with. The first problem I have is with the SRS light. Few days ago I when I started the car the SRS light came on. I am suspecting that is it due to seat belt. So, I just wanted to know if my suspicion is correct. The driver side seatbelt has had issue with clicking in. I would have to try several times before the buckle would snap in the slot.
The second problem is a sound that is coming out of the engine. Couple of days ago as I was going to work, when I would stop at any signal for more then few seconds it would feel that the car is about to die and then it would continue. When I got to work and opened up the hood I heard a clicking sound so I took out all the ignition coils to see the spark plugs if they are ok and one of the ignition coil seemed to be burned out. I am not sure what could have caused the problem and also what else could have been damaged. The last major tuneup I had on the car was only about 10,000 miles ago. I am not sure what else could have gotten damaged. Please guide me on what I would need to do to fix this. What should I worry about when replacing the ignition coil? Should I also replace the spark plug? And if I am to replace the spark plug should I replace all 4 or just the one that goes with the ignition coil? And I am very curious what could have caused the coil to burnout?
Thanks for taking your time to read and answer my problem.
Mayank