Need help

[Marcellina]

I have a 93 Ford Explorer. Engine turns over but won't start, lights, etc. are all working. Starter replaced three years ago, so I don't think that is the problem. What could it be? Battery is several years old. Need help!

 

[zavaral]

What does it do when you turn the key? Does it click, do nothing, does it sound like it's trying to start?