Twice today after logging off and shutting down XP Home I have become aware of a clicking noise eminating from the hard drive. The PC shut down completely and everything was fine. Then approx 5 - 10 mins after this the clicking started and the hard drive light was flashing in time with the noise.
After a minute or so it lets me switch the PC on and use it with no problems at all. Just don't like the idea of it suddenly starting to click for no reason after I've shut it down. Any ideas?

Are you sure its not going into stand-by or hibernate versus shutdown? If your system goes through a true shutdown, all power has been removed from all devices except the powersupply and the on/off circuit on the motherboard.

Sorry, I just click on "Turn Off" on XP which switches PC off as far as possible from this action.

Pushing the button the front of the case does not always shut the PC down. If Bios is setup for it, it actually will suspend the PC until either a keystroke or the button is pressed again. This is call Instant-On from the PC9x specs from MS.

I only press the button in order to restart the PC due to the annoying clicking sound!!

Ok, lets start from scratch. What Make/Model is your system and what OS are you using. Let see if its in the OS or the hardware.

emachines 770 using XP home
nothing fancy/expensive
have used both AVG and Spybot as well as BT Anti-virus scanning to check it's not something embedded anywhere

Welp, that doesnt help...friggin eMachines website doesnt list a 770!

Tell me the process you follow to shutdown your PC with Home. Also do you use the standard look or do you use the classic?

Sorry - had to log off - family problem!
Anyway, I close all the applications down, log off broadband and click START, click TURN OFF COMPUTER then Click TURN OFF when it appears in the centre of the screen. (I use standard look as well and always have)