There is full power to the fuse panel under the hood; but everything inside the car is dead; not even the clock is live. That's as far as I got with the diagnostic before I gave up....please help

Changing a serpentine belt shouldn't affect any of the electrics. Changing a starter only carries a risk when disconnecting and reconnecting the battery before and after swapping the starter motor. Done correctly that risk is low.
So, No clock, no heater control panel, no rear view mirror compass and both power door locks don't work? Does the car still start and run normally? Do the power windows (if fitted) still work?
This still sounds like a fuse issue. How did you test the fuses? Fuses can look OK but still be 'popped'.Somewhere around 2001 some changes were made to the fuse box layout on that model. Is your dashboard fuse panel the smaller square 18 fuse panel or the larger, longer 32 fuse panel?

I'm not familiar with the car or location of relays. But if all circuits are live under the hood and dead inside I would trace the main wiring harness to where it enters the firewall and disconect it and check for corrosion,broken or heat damaged wires and terminals.

some are lower in the drivers side dash under the steering column..others are located in the side of the glovebox.. depends on the model..and some are outside under the hood not far from the battery

[email protected] all the fuses and relays in the 2 boxes under the hood and another one of fuses and relays panel inside the car, front of the driver seat, behind the pull out box next to the hood release handle..Under the hood check inside the one with 8" black square box;Check # 1 slot fuse, it is 60 amps for (+B ), check # 8 slot fuse for Engine control 20 amps, check # 15 slot Fuel pump 15 amps..And check another skinny black box lie next to that box, it has relay F, that is Engine control, check that also...And inside the car fuses panel; Check # 1 slot fuse 10 amps that for Ignition coil, # 8 slot Engine control 7.5 amps, # 12 slot Engine control 7.5 amps..After that recheck the battery post, that maybe needed re-tight..Don't force to tight too much, that will crack and broke the post and the plastic battery body...And check all the ignition wires and spark plugs that are tight or needed to replace..And check all the vacuum lines that are loose and leaks suctions or sometimes they are crack open by long ages..By the way check and recheck all those other fuses and relay for make sure they are good...Believe me that not hard to figure out those problems..You did everything rights so far..That one 100 amps fuse at the + battery post cable was connect to alternator for recharging your battery and give power to other items when car was running..Below that post, the middle cable was connect to the starter motor and the bottom cable was connect to that 8" black fuses and relays box under the hood...

Here's a couple of lifts from the toyota forum:-

1) I think the coin box is the one to the left of the steering wheel. Squeeze the sides after opening it if I remember correctly. Should be others under the hood.

2) It was behind the coin box. I found the fuse for the radio, clock and replaced it and all is well.

Where is the fuse box for 1996 toyota camry? There are several fuse boxes. one is on the lower left side of the stearing wheel (by where you pop the hood) and the other two are under the hood, on the drivers side by the battery.

Most cars have a fuse diagram on the inside of the fuse box cover.

If i were you i would check to make sure nothing is in the cigarette lighter causing a dead short. i know my kids have put pennies, and dimes in mine before, will blow it in a hearbeat, cant even get the fuse all the way in without it blowing. as far as the windows go??? id see about that problem first, maybe they are linked together somehow, but i can tell you one thing, the power windows do have a power window relay, most likely under the hood in the fuse panel... sometimes they are in the fuse panel by the dash inside.. if its the one inside you will be looking for a little aluminum looking fuse that will be bigger than the normal fuses in there, there will most likely be 2 of them.
hope this helps you out.

the level in the washer resevoir is either stuck or burned out. replace that sensor. the air bag light will have to be scanned for codes and figure out which circuit is malfunctioning. its been a while but the easiest places to check are under the dash inside the panels, inside the centre console, or behind the glove compartment. as far as the airbag light, check to see if the horn works. if the "clock spring" is faulty, this controls on the steering wheel will not work. let me know.

The 15 amp dome fuse is in the fuse box under the hood and the 15 amp CIG fuse is in the lower finish panel up under the dash on the drivers side. These are needed for the radio. The above fuses and also the 15 amp Gauge fuse in the box with the dome fuse under the hood are needed for the clock.
So...since both are dead it is likely to be 1 of the first 2 fuses mentioned.

Check power connection by fuse panels under hood just below the center of windshield

You have a switch onthe side of your trans..that lets your ecm know when you are in P or N., Or possible starter.