How can the win7 system not detect the network card?

1. First click on the "computer“ icon and click the right mouse button to select the management;

2, a window appears, select the device manager, you will see a small question mark, Select the device with this small question mark;

3. Right click to select the install (update) driver (if you have already installed the motherboard driver, he will automatically find the driver for the network card, if the motherboard driver is not installed yet) , put the driver CD into the CD-ROM drive, until the small question mark disappears,

4, if you change the bios settings when you reinstall the system, you can not see the network card here (the device does not start, operate the system If you can't find it, you won't install the driver for the device. You need to re-enable the device that was logged out in bios.