On our website, we list all of the platform that can support Windows 7 (Intel 200 series / 100 series / N3000 series / J3000 series / AMD AM4 series) .
If you are finding an installation of Windows 7, you could get it from the following link
=> https://www.biostar.com.tw/app/en/event/windowstool/index.htm .
For the older models, that don't have Windows 7 driver due to chipset manufacturers support limitation.
However, Windows 7 will support most of them by using default drivers in OS.
If there is any problem after installing Windows 7, please use the E-Support to ask for the help.