Hello again chaps,
Well, I think it's a case of "problem solved"...
I finally managed to get an error report out of the obstinate p.o.s. - AFTER I'd tried all of your suggestions!
Googling said error report revealed there was a problem with my graphics card.
A quick visit to a well-known PC superstore resulted in me leaving clutching a shiny new GPU (and 45 notes lighter in the wallet department).
Thanks for all your help and suggestions!
Kind regards,
Don (critter592)