weired sound coming from cabinet(probably it's the harddisk). listen to this.....

hi
from last few days when i switched on my p.c a strange sound comes from the cabinet. i think it might be the hard disk.
i have recorded it and attaching the file, it is in amr format .pls listen and tell what might be the problem.
i observed that the sound comes the moment i switch on the p.c till the time windows load completely after that there is no sound.

ok here's my config-
intel p4 2.8 gz hyperthreding
intel orignal 915gav mobo
2gb ddr1 trancsend ram
320gb seagate hdd
250gb segate hdd
sony dvd writer
lg cd writer.
enterage power 3 gold 450w psu *enterage.in/powersupply.html