I have 2000 Toyota Camry LE automatic. the battery light came on last week, and car died. So bought a brand new battery and it continued...especially at night car dies....so recharged battery and replaced altanator....it continues to die as soon as battery is depleted...i have no idea what to try next ..any help would be appreciated

These links show multiple fuse boxes and fuses which have something to do with daytime running light and lights.
Fuse box location and diagrams: Toyota Camry (1997-2001) - YouTube
Toyota Camry (1999 - 2000) - fuse box diagram - Auto Genius
1999 Toyota Camry Headlight Bulb Replacement, Relays and Fuses Explained - YouTube

Toyota Camry 2000 model headlight fault high beams not working xv20 Camry headlight switching off - YouTube

Toyota Camry Lights Not Working - YouTube

you may have a short circuit in the system seek auto electriction

The only recall items I could find for that vehicle were Headlights, and accelerator cable defects. Those are probably expired by now...14 yrs. later.

I’m happy to help further over the phone at https://www.6ya.com/expert/robert_24775b73ca70da93

Sounds like starter or cable to starter is loose, especially if you just put a new battery in it.

try starting the car and while running disconnect the negative battery cable,if the car still runs turn on the head lights,if the car dies the alternator is weak. I think its weak and can charge the battery as long as the lights are off,but cant keep up when theyare on. so if drive most of the time in the day time you are ok as long as you dont have to start the car too many times. when you drive with the lights on and the engine slows to an idle like when you park the car dies. make sense?

check battery connections my be corroded or battery could be loosing voltage over night

You need to get someone who knows how to use a Multimeter. It is a device that registers how much voltage, is present at your battery when your alternator is charging. Anyone can use one of these tools and they are cheap to buy, just add some AA batteries. Put the negative lead on the negative battery terminal and the positive lead on the positibe battery terminal, set the device to read Voltage and read the display that tells you how much voltage is present when the car is off, then on, and when you turn on different accessories like head lights, AC, etc. your alternator should produce more Voltage with each new thing you turn on. You will see this voltage go up as you read the multimeter on the battery terminals. If you don't see the Voltage go up the alternator is bad.

Now, likely a new alternator should be good, and you said you had the batter tested, hopefully they knew what they were doing. Lastly, I would unhook the aftermarket stereo for a week or two and see if that solves the problem. Also you should check all connections to the battery and to the alternator to make sure there isn't anything loose, that was the problem on my car, the alternator conector was loose and wiggeling and caused the battery light to come on intermittently. Hope this helps you out!!!

Possible EGR valve sticking open.

i'm sure it's not the starter itself that is the problem, have the stater's solenoid checked...it might be stucked. It's quite a lot of work removing the starter but you can do it if you are willing enough to learn. You just need the right idea and tools to do it. Hope this will help save you bucks!

No the alternator won't keep it running on a Toyota, the system is wired much different than most cars, found this out the hard way on same type of car. Test the alternator, raise the idle up to 1500 RPM turn on everything in the car, lites on high beam, ac blower on high, everything, voltage at battery should not be less than about 13.5 volts and not more than 14.7 volts, (clean battery cables first) if all that checks out you have a draw in the system, most common source is the glove box lite or trunk lite, on rare occasions a bad isolation diode in the alternator can cause a voltage draw, another test is to pull off the positive battery battery cable at night and lightly touch it to the battery post, if you see any faint spark there is a draw somewhere in the system, these types of issues can be heck to find, but not always, check what I said to. And last but not least clean the battery cables thoroughly, get a battery brush tool from parts store they are cheap, neutralize any acid with a solution of baking soda and warm tap water.