Given that Windows 7 is now over 15 years old, consider:
: Some custom builds disable Windows Defender, User Account Control (UAC), or Windows Update to force pre-activated licensing behaviors, leaving the system highly vulnerable. windows 7 sp1 dualboot 31in1 oem esd ptbr jan
: This suggests that the software is intended for original equipment manufacturers. However, in the context of end-user installations, OEM versions are typically used for clean installations on computers without an existing operating system. Given that Windows 7 is now over 15