Hmmm!! Still problematical!!
Have ensured that hidden files are displayed and search parameters include system files etc. but still can only find a back-up copy of boot.ini and that doesn't include any entries for a 'no execute' policy.
Had a play with Disk Management to see what it could tell me about the CD. It was recognised and described as 'healthy' and Properties showed the file system as .UDF with 112Mbs used and the remainder unused, however, nothing will allow access
Looking at it using the original Roxio recording program also 'sees' the CD but when a copy was asked for it was refused. Peculiarly, the reason for refusal was that the use of Drive Letter Assignment (DLA) prevents any copying. DLA was suggested during the original burning (by the program) as a means of "allowing the CD to be read on other computers".
I've now totally run out of ideas but would welcome any suggestions from anyone else.
TIA