After dead battery, now won't start

This 2005 LeSabre with a 3.8 v-6 ran fine but had a marginal battery. Then the key got left on overnight leaving the battery totally dead. After jumping the battery and letting it charge, the engine cranked fine but refused to start. Haven't had a chance to check for fuel or spark. Why would a dead battery trigger this no start condition? Thanks guys.

The list of possibilities is too long for me to list. Check for fuel and spark then post the results, that will help to narrow it down a bit.

"After jumping the battery and letting it charge,"

EXACTLY, what does that mean?

Was it put on a charger and fully charged?

When you turn the key to crank, does it it crank fast, or does it slowly crank over?

Double check the connections at the battery.....

If voltage is below 9.6 volts, the PCM will not function...