Check the time/date setting in the first section of the bios screen. I had a similar issue the other day. After the second reboot, I was able to change the time/date, then the other setting changes would hold when I used the "save and exit" option. If your board is oem by dell, etc, then your bios settings are pretty limited and you may not want to change much. If you are overclocking the cpu or ram and the board isn't capable of holding the setting, then there's not much else you can do except raise the voltage, which can damage your components in the long run. I like the auto recovery feature on some newer boards; this option will bring back the bios screen so you can change back the setting that is causing the problem and avoids having to "clear" the bios with the cmos jumper or by removing the battery.