Dear Sallyamci,
most certainly you either solved your problem or sent your tablet back in the past weeks. But I just wanted to tell what I experienced with the Toshiba AT200 (different tablet I know). Perhaps it is of help for someone.

What I have experienced could be described of a stall of the android OS. On a PC you would press the Reset Button or turn off/on the system. On a smartphone you might remove the accumulator to force the system being reset. This is not possible on the AT200 (and I'm unsure about the accumulator in the AT100).

My AT200 recently went black (or did not return from stand by) while in use. In my case the lights weren't on and also did not go on when connecting the power supply.

I put the tablet back into the box planning to bring it back to the dealer on the next day. In the evening I took the tablet back out the box (for one last try) just to recognize that it was warm so I thought it was still running.

The next morning the power led lit when I connected the power supply. And after some time (30min) the tablet could be switched on again.

So probably the battery drained during the night forcing the tablet to turn off (hopefully before the battery was completely empty). That led to a reset.

So one could leave the tablet alone (with no power supply connected) in such case and hope that after some hours (or at most some days if it really was in standby) the low battery forces a power off.

If there's any hard reset possibility (hidden switches) for the tablets I would be happy to know about it. Just in case this happens again.