Well there is no direct upgrade path from Vista to Windows 10 or 8.1. If you wanted to upgrade you would need to upgrade to Windows 7 then 10 or 8. I prefer clean installs because you don't know if there are latent problems in the OS or possibly malware that will carry over in the upgrade or the upgrade may just break something. Plus upgrading is going to require a Windows 7 and Windows 10 license.