Thanks for the tip! In any case, Dell are sending a techie with a new drive tomorrow to look at it. So rather than attempting to "fix" it and embarassing myself if it works, I'll leave it to him/her :P I'll post what happens!
*Addendum* Problem solved after reinstalling new hardware provided kindly by a technician under warranty. Also had to reinstall Recordnow v6 and the updated PX engine to get the burner worker but otherwise back to normal
