1. Press F8 to enter safe mode, and then exit. Select restart or shutdown to start, and then you can enter normal mode (repair the registry).
2. If the fault still exists, please use the system that comes with the system to recover until there is no such fault (if the normal mode recovery fails, please press F8 to enter the safe mode and use the system recovery).
3. If the fault remains, use the system disk to repair it, open the command prompt and enter SFC/SCANNOW(SFC and/) to insert it into the original system disk repair system, and the system will automatically compare and repair it.
4. If the fault still exists, set the optical drive as the first boot device in the BIOS, insert the system installation disk, and press the R key to select "Repair Installation".
5. If the fault still exists, it is recommended to reinstall the operating system.
Another reason is that the power supply of USB interface is insufficient, which may be caused by too many peripherals connected to USB interface. It is recommended to use a charged USBHUB or USB to PS/2 adapter. It is also possible that WindowsXP turns on the power saving mode by default, resulting in insufficient power supply to the USB interface and intermittent failure of the USB interface. Right-click my computer/properties/hardware/device manager, double-click "universal serial bus controller" to go to several "USB root hubs", double-click any one to open the properties dialog box, switch to the "Power Management" tab, uncheck the check box before "Allow the computer to turn off this device to save power", click OK to return, and then modify the properties of each USB root hub in turn and restart the computer. USB devices can resume stable operation, and the frequency should be set as low as possible.
If there is no displayed drive letter, the solution: right-click My Computer/Management/Storage/Disk Management, then right-click the icon of removable disk, click the option of "Change Drive and Path" in the shortcut menu, click the "Add" button in the subsequent interface, then select "Assign Drive Letter", select the appropriate drive letter from the drop-down list next to this option, and click OK. Finally, turn on my computer and you will see the drive letter of the flash memory.