Hi Xercess and welcome to Windows 7 Forums
Given what you have said about the state of your electrical supply, especially at night, I would consider switching off at the mains socket when you are not using the computer. Also consider using a surge-protected adapter. A UPS (Uninterruptable Power Supply) might be useful, to enable you to safely shut down your computer should the power fail whilst you are using it.
As regards the settings in the BIOS, unless there is a specific reason why you would want your computer to restart after a power failure, or to boot on LAN, I would set the options to OFF. Check your motherboard manual for details. If you are unsure how to do this, let us know what motherboard you have and we'll guide you.