Key will not start car

[Hawleymoma]

:exp:I have a 2001 Explore Sport that I use for work and to get my kids. I have two small children so its an emergency that i get this fixed. When i stick my key in the ignition everything cuts on but the car will not turn over. We have checked the starter and the alternator which seem to be fine. The theft light does come on however it doesnt blink rapidly just how it normally would when car is off and locked.. someone had told me that the chip in the key was bad so i grabbed my spare and used it... BY ITSELF with no other keys attached.. dropped my kids at the sitters and when i came out it started just fine so i went to work, i came out for lunch and NOTHING! when you turn the key and hold it there is one click.We have no clue what it could be and now i have no vehicle... PLEASE HELP!

 

[Sams01XplrSprt]

welcome

 

[Tbars4]

...This should be of some help...
http://www.explorerforum.com/forums/showthread.php?t=234975&highlight=pats

 

[BrooklynBay]

Welcome to this forum! It sounds like the PATS system.

 

[Dopler174]

It could also be a bad starter silenoid.

 

[my98nnj]

Or a poor battery cable connection.
Check for corrosion, clean up both the pos. and grnd. cable connections.