There are more than a dozen of beeping sounds to be
interpreted.
1. If you still have your motherboard manual, refer to it and tell
us what BIOS it is using. Otherwise, tell us your motherboard brand
+ model number.
If you have lost it and can't figure it out, please at least tell
us the model number.
2. Turn on the computer. Listen carefully to the beep sounds. Any
specific patterns? Like long, short long long. Also the pitch. Are
all high pitch? All low pitch? Or some high pitch, some low
pitch?
3. On the monitor, is there any error messages shown?