alternaut, Virtual1, ryck

Thanks for your replies and Disk Warrior it will be. I have "meant to" get it on a couple of occasions in the past, but have procrastinated after Disk Utility seemed to sort things out and lull me into a sense of complacency. blush
By the way ryck, no, I do not have any other "devices" attached.
Another of my naive/stupid questions :- If one (me) was making another (obviously most recent) back up, can/would the possible underlying problems be copied over e.g. data loss due to bad sectors caused by degradation of the platters or any other such reason. confused How dim/vague was that? crazy
Ironically, this evening when I have switched on, the computer started up in "only" 3 minutes and at the moment "everything" seems fine at the moment in "general" use. Mind you, I have not tried FWTDM wink or repairing the disk. smirk
Thanks again. Regards. Mike