Win7 system computer boot display missing operating systems how to solve

1, after the boot screen screen missing operating system;

2, check the computer USB interface is inserted with mobile devices: U disk, mobile hard disk, check the optical drive whether there is a CD-ROM;

3, the U disk, CD-ROM after the restart of the computer. Can be forced to shut down, that is, hold the Start button for a few seconds after the computer will automatically shutdown, a little stop for a moment, boot;

4, the usual U disk, mobile hard disk, CD-ROM, and so on in time to remove, to prevent similar conditions occur.