Thanks all.

I tried using a 2007 disk mega pack and that installed ok so perhaps that 2008 disk is now faulty.

Will upgrade later to 2018.

when at my tyros I use an old w7 computer with a 21" monitor situated at the tyros music stand, my eyesight is not good for reading manuscripts (books) at that position, I was 81 years this week. Still play but more slowly.