To format the hard disk, you need to install WIN7 first, otherwise everything will fail. Different from before, the startup and boot information of WIN8 is divided into two hidden partitions on the hard disk independently under the system partition. If WIN7 is installed in WIN8 environment, it will not be able to start or boot.

Hard disk partition must delete those two hidden partitions, otherwise WIN7 will not be installed, and WIN8 system error will be prompted when starting.

It doesn't matter about OEM authorization. After installing the grid, the same version of WIN8 will be automatically verified as genuine.

OEM is generally only available for brand machines. If the statement is equipped with WIN8 system, it is genuine verification, and there is information in BIOS.

Otherwise, even if it is pre-installed, it is not necessarily genuine, and it will be installed in the computer city, and the activation is very simple.

Some online tutorials about downloading WIN7 from WIN8 can't be used. Without exception, the preview version is used, and the preview version is ok.

But the official version can't. You can try it if you are interested. Whether it is VHD or something else, it is almost impossible.

WIN7 downloads WIN8 to form a dual system 100% success, as long as the operation is not wrong.