hi Matt,
Thank you for your reply. My hard drive is an I.D.E. type, I fitted it in May '07. I took your advice and pushed down on both connections, they didn't seem to move at all, restarted and my drive was found on restart. I didn't think it would be that easy to fix. Is the clicking sound an indicator of a loose connection? Thank you again.
Regards tech_no

Just checked my event log, system tab, I am still getting an error on disk on start up, it seems.