PLZ HELP !!..1999 Ford F-150 won't start...

1999 Ford F-150 V-6 motor Automatic transmission....Truck was fine as far as I know, being driven daily, Son drove it to meet me and came back, parked it, then about an hour or so later he got in it to leave again and it just wouldn't start..All electrical comes on just fine,all lighting in and outside of truck is bright, you turn the key to start and nothing happens, put new battery in approx. 3 wks ago,so battery cable ends are clean. Fuel pump can be heard coming on so it is getting fuel...No noise except key being turned to on position...REALLY would appreciate any help with this problem !

no crank either? check to see if the theft light is blinking(instrument cluster), possibly starter relay, or neutral safety switch. If the theft light is not on use a test light and check for voltage at the starter relay(right rear of engine compartment) tn/rd wire while cranking

Thanks for the reply..no, it does not crank or attempt to..It is as though you are trying to start it while it is still in Drive...that make any sense ?

Thanks Carlos80....it was the starter relay that went out...he tested it and the truck cranked right up....ha...so he has gone to the Auto parts store for a new one now...Thanks again for your time and help on this one !!