"Ken" wrote
|I downloaded Win 10 and burned DVD's when new versions (updates) were
| available since I had several computers running Win 10. Although I hope
| I never need to use any of them to restore Win 10, I did use one for a
| friends computer that crashed. My question is: Are the oldest versions
| no longer usable for such a purpose, or can they be used and brought up
| to date in spite of being old versions?

Officially the versions are only supported for 12-18
months. On the other hand, MS will probably be
begging people to use Win10 for the forseeable future.
It's hard to imagine them refusing to update freebie
adware.