: Digital preservationists often upload ISO images of original installation media. These are generally safe for historical research but require a valid product key found on the computer's COA (Certificate of Authenticity) sticker.

Before searching for a download, check if your computer has a built-in "Recovery Partition." Most OEM manufacturers included a hidden section on the hard drive to restore the PC to factory settings. How to access it: Press a specific key (like for Dell, or for Acer) immediately after turning on the power.

There are no legitimate, safe, or legal downloads available directly from Microsoft anymore. Any website offering “Windows Vista Home Premium OEM ISO” or “OEM activator” today is almost certainly distributing: