If your laptop has even a half-dead battery, you should have been able to boot it without the AC/DC plug. Possible that the DC daughterboard got hit pretty hard, but it should still work off the battery then. When you try to power it up do the fans spin at all? If not, then the motherboard isnt even getting any power through to them which is a bad sign (Its dead in other words.) I would make sure you have the HDD backed up, and if you're out of warranty already, open it up and try to reseat everything/check for damage.
You could also try shaking the laptop slightly ( take out the HDD before you do this ) to see if there is any rattling. There shouldnt be any, and if it sounds like a small piece of something is bouncing around, you can be fairly certain the damage is extensive.