Hi Mary -
The first thing you should do is consult the set up procedures on Page 8 / Section 4 of the manual
. This will assure that you have completed and exited this important section properly.
If the TV should lose power (power outage, blown fuse or circuit breaker, cord removed from the outlet, etc.) the TV will likely need to have the setup performed when powered again for the first time. Likewise, a TV that is plugged into an outlet controlled by a switch, will lose power when the switch position is changed. Since switched and un-switched wall outlets look the same, you will need to unplug the TV and plug in a table lamp or similar and operate switches to see if it goes out. You will need to try both the upper and lower outlets as they can be operated independently of each other. If you find that the outlet is switched, you will either have to stop using the switch or find another un-switched outlet to power the TV.
I didn't see it mentioned in the manual, but some TVs have a dedicated power and a dedicated on / off button
. If the power button is set to off, the TV will shut off and the remote will not be able to turn the TV back on until the power button is turned back on. The on / off button on the TV allows the TV to be turned on and off with the remote - or the on / off button on the TV. Again, this will only work if the dedicated power button is on. If the power button is set to off, it may be causing the TV to lose the set up information - requiring that it be done again. Make sure that you are using the remote to turn the TV on and off - or the correct button on the TV if you do not have a remote.
If all fails, you might want to contact Sanyo directly. According to the manual, they can be reached at 800-877-5032. I hope this helps & good luck!