I recently re-formated my computer and the sound work before I formatted it, but now I has no playback and it tells me to add hardware but it still doesn't work... ITs also in the sounds and audio devices properties it says NO AUDIO DEVICE. So please help me

While installing the drivers for the device one of the option you get is download the drivers from the internet ( internet connection should be on),
Other option is finding out the manufacturer of the hw and model, then you can search for the driver on the internet or you can download it from the manufacturers site.
Hope this helps