everything as in cpu setting or motherboard setting? i'm not exactly experience in the technical side if you could guide me thanks
There should be a small button or battery on the motherboard which controls the CMOS. if you hold that button, or pop the battery out it should reset all your BIOS settings back to default.
To adjust voltages, however, you'll need to access the BIOS. It should tell you what button(s) to press to access those menus, somewhere on the screen.