i have a 98 ford explorer with 105k that has become our third car and is rarely driven. It its in the garage for weeks at a time. Recently I pulled it out to repair the mirror. When I went to put it back in the garage, it would not start. The battery is new and it cranks strong, but will not turn over. The fuel tank is 3/4 full. Could the fuel pump have failed or could water have accumulated in the tank?
Check the spark and check for fuel pressure. Try banging on the gas tank with a 2 x 4 to start up the fuel pump. A 2 x 4 is a standard tool kept in some tow trucks for this purpose.
Guessing is too expensive. If you know a mechanic with good troubleshooting skills, give him a call.