According to the following steps:
1 After entering the bios, find the setting with the word sata (different motherboards are different).
2. Change the interface mode of computer sata hard disk from AHCI mode to IDE mode,
3 Settings from the USB flash drive, needless to say. Save, exit and restart.
4 Insert the USB flash drive, and you can't detect the hard disk when you enter the PE.
You can install your system for the rest, hehe.