1. If it is a windows operating system pre-installed by ASUS, you can use the power-on F9 key to restore the pre-installed system.
2. For the non-pre-installed operating system, you can use USB flash drive and CD to install the system. Press the ESC key when booting, select the startup items of U disk and CD from the startup items list, enter the system installation interface, and install the system. The installation process can refer to the video tutorials on the following websites.
How to install the system: /u/UNTQ2NzkxOTQ4/videos
I hope the above information can help you, thank you! If the above reply still doesn't help you solve the problem, you are welcome to continue asking.