What do beep codes mean?

Beeps codes are the audio beeps that the motherboard will output when
your system has a problem. Generally they can be used to identify some
problem (usually associated with a non booting system). Below are some
basic beep codes and their possible meanings:

one long and 3 very short beeps - video related (due to some newer video
chipsets not being supported in "BootBlock" this may also indicate a bios
rom checksum failure.)
continuous beeps - memory related
no screen and no beep - CPU related