DELL E6430 no sound after installing WIN10

This problem has been going on all day, and it's time to get out of work.

The reason: A E6430 notebook, the system was re-installed in the morning after the Win10 1607, the default speaker does not sound, but connected to the headset has a sound.

Solution: IDT Network card driver is not compatible with WIN10, resulting in non-normal use, the online method is to download the official website win7,win8 corresponding 64-bit driver installation.

sound card driver:
idt92hd90bxx, install Win7 official drive is good, WIN10 system default drive sound without the lower limit of rotten.
* Note: When using Win7 official drive, please install the driver after the system service inside the "Audioservice" disabled, Startup type is also disabled, otherwise it will appear plug-in headphones pulled out (repeatedly n times), resulting in the sound card, and headphones sound normal situation. If you've done it my way, adjust the sound options-speaker Properties-enhanced feature Select Disable all, or cancel disable to adjust when you find that the sound is not normal. Headphones and speaker cannot be set to fixed.

With the solution provided by netizens.

DELL E6430 no sound after installing WIN10