my milwaukee m18 drill driver won't turn on at all, what's wrong?

Most likely a dead battery or bad connection. Check the battery pack indicator. If it shows no lights, the battery is discharged or defective.

Fix:

1. Remove the battery pack from the drill.
2. Insert it into a Milwaukee M18 Rapid Charger, catalog number 48-59-1808.
3. Charging will only begin if the battery temperature is between 32°F and 104°F. If it's colder or hotter, wait until it's within that range.
4. Charge until the charger indicates a full charge.

If that didn't work, the battery contacts on the tool or battery may be dirty. Remove the battery and clean the metal contacts on both with a dry cloth.

Heads up: New batteries must be fully charged before first use. Never force a battery into the tool.