: eBay and Newegg (via third-party sellers) are the most common places to find physical "Retail Box" versions or "OEM" discs.

: Includes "Hyper-V" which allows you to run Windows 7 in a Virtual Machine (VM) safely.

: Tied to the first motherboard it is installed on; cheaper but non-transferable.

: Modern hardware (especially CPUs from Intel 7th Gen or AMD Ryzen onwards) often lacks official driver support for Windows 7. Alternatives to Consider

: Ensure the seller offers a "Guaranteed Activation" or a money-back guarantee. Scams involving used or blocked keys are common for older Windows versions.

: Microsoft no longer provides security updates or technical support for Windows 7. Using it online makes your system significantly more vulnerable to malware and hackers.

Since this is "legacy" software, your options are limited to third-party retailers: