SOURCE and more info at: www.d-a-l.com (posted by chou)
Award BIOS uses beeps of varying duration. A long beep will typically last for 2 seconds while a short beep will last only 1 second.
Award BIOS also uses beeps of different frequency to indicate critical errors. If an Award BIOS detects that the CPU is overheating it may play a high pitched repeating beep while the computer is running.
1 Long, 2 Short
Video adapter failure Bad video adapter
Repeating (Endless loop)
Bad memory or bad connection
1 Long, 3 Short
Video adapter failure
Bad video adapter or memory
High freq. beeps (while running) CPU is overheating
CPU fan failure
Repeating High, Low beeps