Beep codes can be used as diagnostic indicator.3 beeps indicates system board failure.
It may involve any of the following failure :
Chipset Error (North and South bridge error, DMA/IMR/Timer error)
Time-Of-Day Clock test failure
Gate A20 failure
Super I/O chip failure
Keyboard controller test failure
In this situation the system board needs to be replaced to fix the system.Is your system is within warranty,repair/part replacement is covered by the warranty?