This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
Most likely, your battery-- also called the "BatRAM battery" needs to be replaced. When the GS is OFF, the battery supplies power to the clock and its attached 256-byte RAM. This small RAM is where Control Panel settings are 'remembered'. If, upon power-up, the GS believes the Control Panel settings have been messed up due to a low battery, it will reset the settings to their default (check-marked) positions. By: Rubywand