When you turn on your PC–and all is well–you typically hear a single beep from your computer speaker, signaling that all is OK. If things are wrong–and the computer BIOS senses that things are wrong–a series of beeps will be emitted. This is the beep code. Based on the number of beeps, you can look up the meaning in your motherboard documentation and often diagnose the problem. Obvious things to check are whether your video card, processor, and/or memory are plugged in and seated properly.