98 Engine won't start

I replaced the engine in our taurus & the car started. After hooking everything else up the car will not start. Everything has been checked & double checked. Still nothing. The windows go up & down & the lights go on. Any suggestions?
Thanks,
Scooter

You'll need to describe better what it does and does not do when it "will not start." Does the starter motor turn, but it won't start? Do the lights on the instrument panel come on when the key is turned to the "run" position? If you leave a door open and try to start the car, what do the interior lights do (dim, go out, no change)?

If the starter motor cranks, do you have fuel pressure?

Did the car get jarred (like dumped off a jack stand) and if so, have you reset the fuel pump inertia switch?

-Rod