Whirlpool

Upon startup of my PC this morning I noticed a click click noise coming from inside my PC.....I initially thought a wire was touching a fan as it was clicking in rapid succession...I ripped off the side of the case and discovered it was the HDD....Now I know that when HDDs go click it means they will die rather soon but how soon???? I did a complete backup this morning just in case..

HDD is a 15 month old WD 250Gb that was in fact a warranty replacement for another WD that died on me after 2 months...

It stopped making the noise after a short while...

..RC.. writes...

It stopped making the noise after a short while...

yep, sounds like the drive is dying. You have already done the backup so now it's either a case of wait and see if it dies or get hold of the Western Digital testing tools and test the drive and go from there.
In either case it should still be a warranty job i think but if the drive TESTS as fine and seems to run ok ( for now) chances are it won't test as faulty when you return it and then you are up for all the freight charges etc for nothing.
I would remove the drive and put a new one in and use the existing drive for something non critical, or just cut your losses and bin it.

..RC.. writes...

Now I know that when HDDs go click it means they will die rather soon but how soon????

not always, is the drive clicking every few minutes or only on startup ?
in general the clicking noise is the drive thermally calibrating IIRC
however if its happening constantly it indicates the drive is failing
whereas only on startup *may* indicate it is failing
or it could be normal operation

What's that kids song called? Click goes the shears or something....anyway you've got two extra clicks =P.

Well you've backed up which is great. If it only clicked at start up I wouldn't be too worried but then again it is something which you say is not regular so that is a telling sign.
Just watch and wait I suppose and only use the drive for temporary storage/files so if it does suddenly die you don't lose anything.