I was totally unaware of this issue until I had a customer talking about this issue today, so I then went to the ASUS website and checked the ASUS motherboard B150M-A a popular model. It had listed Windows 7 as a supported O/S and also had this note: “Please refer to ASUS website and download “Windows® 7 installation guide” and “ASUS EZ installer” to install Windows® 7”.
I found this information on their FAQ page: “Based on the chipset specification, Skylake (H110/H170/Z170/B150/Q150/Q170) and Braswell platform require USB 3.0 drivers to be preloaded in order to use USB keyboard/mouse during Windows 7 installation. This section is a guide on preloading USB 3.0 drivers and installing Windows 7.“
I found the ASUS AZ installer on this page: https://www.asus.com/us/Motherboards/B150M-A-D3/HelpDesk_Download/
and the Win7 Installation guide (English) near the bottom of this page: https://www.asus.com/us/Motherboards/B150M-A-D3/HelpDes….
Hopefully this will allow you to install Windows 7 on the ASUS Skylake boards from now on w/o issue. I’m sure there are similar work arounds on the other motherboard websites you just need to see what is said under specs then compatible O/S about windows 7.