It could be a low or dead battery. The 2000 Sport was notable for causing a heavy draw on the battery when being started and, having one, I found that installing the most powerful battery that will fit is the solution. I got mine from a battery shop specialist. Until I did this the Jeep ate batteries fairly often and of course they failed at the most inopportune time or place. Will your work with a jump start? If so it is a good indication your present battery if low. Good luck.
could be a faulty neutral safety switch in your console, try putting the shifter in neutral, then try starting it, if it works you will need to replace the switch. or could be a problem with fuel delivery...here is a link with a different answer (about halfway down page); http://autorepair.about.com/library/faqs/bl122f.htm
Does it turn over? Does it have fuel, spark and compression?
What is it doing? ddus it turn over but just wont start?
Could be a loose or corrodedbattery cable.
starter motor or ignition
turn key over turn key over
2002 jeep liberty part time light wont turn off
Does it turn over? Does it turn over?
my 1994 jeep larado turns over then dies out
If your 2001 Jeep Commander randomly stopped working and won't turn on, you likely have one of two problems. Your battery is dead, or your alternator is dead.
Recheck the connections, you may have missed one, so its flapping about in the breeze.