Noisy WD2500KS hard drive

[AgrFan]

I have a Western Digital WD2500KS hard drive in one of my folding boxes that is really noisy. It sounds like a popcorn machine. The box has a fresh install of Win XP Pro w/SP3. No antivirus software is installed and the drive is regularly defragged. I'm pretty sure I'm not running any tasks in the background that would be causing excessive disk activity. It doesn't matter if the indexing service is turned on or off. Not sure if I'm missing something in the configuration or this is normal for this drive.

Specs:
CPU: E5200 (stock)
Mobo: GA-G31M-ES2L
RAM: 2x1GB Cosair XMS DDR 800
HDD: WD2500KS 250GB SATA-II
OS: Win XP Pro SP3

Any suggestions?