1, the system has disabled the USB service generally if nothing has been set, this situation is not going to happen, but some friends may like to use such as Jinshan bodyguard or 360 Security defender Optimization System, disabled USB service, you will also appear USB interface is not available system Plug and Play service is disabled to cause USB is not available.
Solution: Open the Startup item setting!
2, front USB interface is not available if we encounter a front USB interface is not available, in particular, the first time the new machine with USB, the reason is not to say that the U disk to connect the rear of the USB interface, the rear USB interface is provided by the motherboard, the problem can be solved.
3. USB function Disabled in BIOS setup
If you are operating a computer system this may be the case, the motherboard BIOS has a USB control switch, the default is turned on, if due to error set BIOS or BIOS error may cause USB interface is disabled, so if the above situation, we may wish to check whether the BIOS settings disabled USB. Solution: Restart the computer, press the Del keyboard, you can enter the BIOS settings, enter the BIOS setup interface selected inside the "Integrated Peripherals" item press ENTER
has been translated into Chinese and English, step antu operation, select enabied for open! Select Disabled to disable!
4, there is another version of the BIOS diagram below enter the BIOS setup interface select System Device Setup Press ENTER, select the USB Function selection enabied to open! Select Disabled to disable!
5, USB interface damage or motherboard failure
If the above three kinds of situation still can not solve the problem, the first exclusion is not a U disk failure, then you need to pay attention to the computer USB interface failure is the majority of the motherboard problem, recommended to take maintenance.