For computers that can't identify usb drive, we can use the F8 key to enter the security mode by restarting the computer, and uninstall all usb flash stick in the device manager. Once again restart the computer to enter the normal mode, then insert the usb stick into the computer, the specific operation is as follows:
1. Insert the usb device into the computer usb interface,
2. Click "start" menu, click "run", enter "CMD" in the input box, and click "ok" button.
3. Execute the following two commands in the command prompt window.
Reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control Session Manager\Environment" /v "DEVMGR_SHOW_DETAILS" /d 1 /t REG_SZ /f.
Reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control Session Manager\Environment" /v"DEVMGR_SHOW_NONPRESENT_DEVICES" /d 1 /t REG_SZ /f.
4. Restart the computer, click "start" menu, open "run", and enter "devmgmt. MSC" command,
5. Click "ok" or right-click on the desktop "my computer",
6. Select "properties" in the pop-up menu,
7. Click the "hardware" TAB,
8. Click the "device manager" button below.
9. Open the device manager and click "view" in the menu bar - "show hidden device".
10. Double-click the "universal serial bus controller" project on the left mouse button, and uninstall the gray project shown and the usb stick large storage device.
11. Then right-click on the "universal serial bus controller" project and select "scan check hardware changes" in the pop-up menu.
Unplug the usb stick and plug it in again to see if it's OK.
12. If it is not good to re-insert, right-click the "USB Root Hub" project under "universal serial bus controller" and click "properties".
13. In the open window click the power management TAB, and remove the "allow the computer to turn off this device to save power", click "ok" button (in turn modify the property of each USB Root Hub).