Hi,
The buzzing alarm is a beep code which indicates a hardware problem.
Try removing the system memory and clean the brass contacts and the
slots it goes into, then reseat the memory and try to boot again, the
memory looks like this >>>>>>>
What you need is a soft, clean, dry paintbrush.
Remove the powercord from the back of the PC.
Start by removing the ram and clean the contacts with the brush, then clean the brass contacts, reset the memory and the powercord and try booting the computer.
If it still won't boot count the beeps and how long they are and post back here.
Regards.