REcently my PC seems to be making some ugly noises - grinding and whirring types. These seem to be coming from the vicinity of my C drive. In the last couple of days the system has taken to suddenly shutting down in teh middle of activity. Is this a symptom of imminent HDD failure? I have backed all of my files and while I have added a second HDD as slave I'm a bit scared of installing a disk and OS etc.