1996 Ford Explorer

I have a '96 Explorer, Yesterday was pretty cold, went out in the AM and it started right up, then went to go home yesterday eve and it would not start. It turns over and acts like it wants to start, but wont do it. Is it the fuel pump or could it be something else? I checked the fuel reset button, it was not engaged. Later in the day it started, I turned it off and now it wont start again.
thanks for any replies...