Something is draining the battery.
Car starts fine from a jump or charged battery, however if car sits over nite then the battery is drained. Same problem with new battery and alternator.
Help?

If you have an amp meter, with the car turned off, you could take out one fuse at a time and measure for current flowing accross the contacts where the fuse is installed.
If you don't have such a device, you could try taking out one fuse at a time and leaving it out overnight to see if your battery holds a charge. Or you could take a fuse out one at a time and take the pos. battery cable off and see if a spark is formed as you touch the pos. batt. cable to the pos. batt. terminal.
Once you know what fuse circuit the short is in, you can track things down from there.
Or, if you don't care for such hassles, you can put a switch that is installed under the hood on the positive batt. lead that you have to switch off at night and on in the morning. This would be in effect the same as disconnecting your battery each night so that it can hold a charge.
Good luck!

You could also check your grounds. If any of your grounds are off or they have a bad connection it could cause a short and thats why your battery is draining overnight. Either that or check to see if any of your lights stay on when you close the door to lock it. Hope this helps