hello/ new here, need help please..

I have just bought 1997 4.0 land rover have it home 1 day n cant get it to start!! Has power,say's. Alarm fault, reading on this I tried several things disconnect battery enter code1515 along w code given w truck, locked n unlocked w key pad, and to no avail still no start, engine is immobilized, can anyone help?? Thks