OK. As I only had about 9 Gb left on my C: partition, I used
GPARTED 20.02 (booted from DVD) to steal about 50 GB from a Ubuntu partition, so that I could Upgrade to 10.
All went well, and my C: now has 50+ GB free. Except-
Now I can no longer boot Windows. Using GRUB, my Ubuntu (shortened by 50 GB) still boots OK.
I tried both Win 8.1 and Win 10 install DVDs to repair, but they both eventually said "Unable to repair"
Basically, I am told Winload.exe is missing. But it is not.
It appears to be something to do with uEFI, which I do not - I CANNOT - use, as my BIOS is too old. (gee- 7 years old!)
Believe me, this uEFI crap also sometimes causes grief in my GRUB and Ubuntu partitions as well, if it is any consolation to you Windows techies! ;-)
Once Again : my BIOS DOES NOT SUPPORT uEFI! Understood? (it's happened before- "experts have said to activate uEFI)
The last message I was able to recover from logs was 0cx0000025 missing winload.exe.
Any suggestions on how to fix my Win-8 partition? I cannot even mount it in Ubuntu now, because of this damm fast-boot thing that I turned off at one time, but has now been turned back on somehow. I suppose I should keep Window's FASTBOOT off always.
Is it of any use to me?
Please don't tell me to upgrade my mainboard. That's what the last guy said! ;-)