I get a red bar when trying to install windows 7 DVD, and it freezes

Windows 7 doesn't support the new UEFI GOP (Graphics Output Protocol) and requires VGA option ROM (BIOS interrupt 10 (INT 10H)). Win8/10 supports GOP and reads the UEFI Logo and displays it during boot for a smoother boot. And it seems that your UEFI always turns GOP on and disables VGA, so Win7 can't be used and hangs at Starting Windows with the graphic artifacts.