Upgraded Win7 to Win10 - now very slow boot-up and poor performance

Can I just add to that IF or when you do a clean install. My experience of having Linux Mint installed is that it can prevent other things being installed afterwards. Historically I have had to actually wipe a drive (not just format it) to be able to install anything after having Linux Mint installed. Presumably that has wiped the MBR. I have only had this with Linux Mint - not with other Linux distros. Something different about it (very unscientific comment I know!).

So if leaving the Linux Mint partition in tact and then installing Windows - if it won't install then it would be necessary to back up all the Linux files as well (and make a note of programs and settings as well.

From there I would then wipe the hard drive (I've used Parted Magic for this). Or at least wipe the MBR (parted magic does that too and it may suffice and is quicker).

Then install Windows then reinstall Linux. Then the rest

Actually wiping a hard drive (filling it with zeros) does seem to rejuvinate it a bit too.

That's curious, @Hazel123, and surprising.

We are at risk of swerving off topic if we pursue discussion about Linux (Mint). But I'll just observe that your experience is not, as far as I know, typical. I've had Mint, and Linux Lite, and MX Linux and PCLinuxOS, all installed variously as dual or multi-boot on my 'main' computer alongside Win7 over the past 5 years or so, and in particular I have upgraded/reinstalled Mint. I have never found it interfered or caused problems with other setups.

I wonder if part of the explanation is to do with the MBR. When I Install Mint (or any other Linux distro) I keep Grub away from the MBR. I install Grub on the same partition as the Linux distro itself. I keep the Windows bootloader in the MBR and use EasyBCD to tell it where to find the Linux Grub. That way Windows remains intact on its own partition, and any Windows updates don't interfere with Grub.

I'm into the realms of guesswork here , but I wonder if your experience of Linux Mint "wiping the MBR" isn't actually the result of installing Mint in the default configuration - which means it overwrites the Windows bootloader in the MBR. Pretty much all Linux distros do that, unless you do a manual install and locate the Grub elsewhere. I don't know why or how that would "prevent" subsequent installations though.

The radical wiping/obliteration of the entire drive .... and "rejuvenation" .... seems to me like the nuclear option. The day when I have to do that may come. But please - not just yet!

I have Windows and Linux on my GPT drive.
On a UEFI - GPT system, the two OSs can be completely independent.
- EFI Fat32 partition has both boot managers (Windows boot loader and Grub)
- Each OS has its own partitions
Windows = MS reserved + C: + Recovery
Linux = OS + Linux swap

I don't have a Linux option on Windows boot loader and Windows option on Grub.
Windows is my first priority on BIOS.
When I want to run Linux I launch the boot menu (F12) during POST and select to boot using Grub

You all know more than me about installing Linux . Also may have been the particular low spec machines I was installing on.