Multibooting Windows 10
One of the factors that contributes to our pessimism surrounding reinstalling Windows is that we desperately don’t want you to lose anything. We’re kind like that. But there is another, slightly frivolous way to do a reinstallation if you’ve got working hardware to play with: you can turn one Windows installation into two. If you have a second drive that is able to support a Windows 10 installation, or enough access to your current Windows 10 installation (and enough free space) to be able to trim down its drive using Disk Management then create a new clean partition, you can install a second copy of the operating system alongside the first. Simply select a custom install, and then point Windows 10 at that spare disk space – it should do the rest for you. It’s questionable whether you’d technically need a second Windows licence to do this – you can only possibly use one instance of Windows 10 at a time if installed this way, so it shouldn’t be an issue, but the Microsoft EULA does suggest that only one instance is allowed to exist. Take that as you will. You’ll likely need to switch off BitLocker before partitioning your drive, and if you use Windows in this way, you’ll want to do this anyway, since an unlocked filesystem on your original install can be easily accessed on your new one. Copy everything to a safe new location, make sure you’ve got everything, and you can ditch the original install – and if you’re likely to use the new installation as your main copy of Windows, you’ll need to make sure it’s first in the boot order. It should be by default, but you may need to poke around in your BIOS/UEFI settings to select the correct drive, or set it through the Advanced system settings link from the Control Panel’s System tab.