Some PCs come with video and sound built right into the motherboard, that flat platter of circuitry connecting all your PC’s parts. The manufacturer shrunk the sound and video circuitry into a little chip or two , stuck them on the motherboard, and connected them to the VGA and sound ports on the back of your PC. This design saves you money, as you needn’t buy additional cards to handle specific jobs lime playing audio or video.

But if you upgrade your PC with a more powerful video or sound cards for gaming, the build-in circuits can cause problems; your PC won’t know whether to use the built-in circuits or the newly installed ones. The solution is to tell the BIOS to stop using the built-in circuitry and switch control to your newly installed card instead.

Or, if you add a video card but want to use two monitors, you may need to tell the monitor to use the motherboard’s video in addition to your newly installed card.