R40 Seagate 160GB: head clicking noises, load/unload cycles?

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I have an R40 Thinkpad with a 3rd party (non-IBM branded) 160GB hard drive made by Seagate (ST9160821A)... I'm running WinXP + SP2... laptop is always plugged in (ie not running on battery power)

I have noticed that ever since I have been using this drive (about half a year) sometimes there's is a clicking sound (just one single click) and the whole system is then inaccessible for the duration of this sound (which is probably less than 300ms).... by inaccessible I mean that I can move the mouse, but when opening/saving/editing files the hdd access is not possible (though as stated, only for a very short while)...

this kind of sound will happen maybe 10-20 times a day (with laptop being used for 10hrs/day) with no apparent pattern (ie: this clicking is not happing at regular intervals)...

this leads me to a conclusion that this 'clicking sound' is infact the parking/unparking of drive's head.... but WHY is this happening ? From what I read this behaviour will lead to an increase in 'load/unload cycles' which in turn leads to shortening of the drive's lifespan... there are two possibilities:

a) somehow IBM Thinkpad BIOS doesn't like this third-party seagete drive and the fact that this is a non-IBM branded hdd is causing all this

b) this could be happening beacuse of power management features (parking/unparking for saving power)... BUT as I said earlier I'm running always plugged-in and on 'always-on' power scheme (I'm never using this laptop with battery-only power)


PLEASE HELP !
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