To reinstall the system with USB flash drive, at least 4G USB flash drive must be installed accurately. If your system exceeds 4GB, you should prepare an 8gb USB flash drive. And plug in the computer, the computer downloads peaches and installs them. After opening, follow the prompts to complete the start-up production of U disk PE. After the production is completed, download or copy your favorite system package to the corresponding folder on the U disk. For example, if it is in iso format, put it in the ISO folder of the USB flash drive. It belongs to gho. In the gho folder. Then turn off the computer installation system. Then press the shortcut key (such as F 12) at the same time when turning on the computer, and some of them must click the shortcut key desperately. See the figure below for shortcut keys of each computer motherboard.