I ran in to a further problem with copying the files onto a new DVD - there seems to be a major issue with Windows 10 and DVD writing - I can read CDs/DVDs and I can write CDs but not DVDs. I keep being told to insert a blank disk into the writer. Tried all the fixes out there in Internetland to no avail.
Anyhoo, eventually I did find ISO files for both disks online as suggested by Saab Dastard and downloaded them which was a very slow process but installation was no problem and I authenticated it with my original purchase serial number.