Computer encounter several beeps when booting

I have notice this problem when I started to boot my computer to install the Windows XP.
At first I thought it was just a sound coming from a phone or something but when I do the repetition of booting the beeps was continuously sounding. I unplug the computer and turned it on again.
I went back to BIOS set-up to boot again the devices but still the beeps are keeps on beeping.
I did not continue boot my computer because of the problem encountered.
What will be the exact problem of the computer why are the beeps always interfering?
Please help!

