Hi there, thanks for your reply - no the system wont boot up at all if the noise begins as soon as you start the machine up. If the machine is already running and the noise starts then it freezes. The thing is it is quite loud, a bit like something catching on a desktop fan, and along with the grating sound there's a kind of screeching. To me it reminds me of a bearing failing on a wheel. If you place your hand under the front port side of the machine while its making this noise, you can actually feel the vibration of whatever it is that is spinning and catching. Its as though something is spinning very fast, but is out of balance.

Thanks for letting me know thats where the hard drive is located. I suppose thats one of the most expensive parts to replace??? Id be very gratfeul to hear any other thoughts you might have on this.

Regards

Shaun