system restore I think I will get no benefit from it because this problem exists since I bought the device.
Well, if this issue appears from first day of purchase, then an hardware issue might be possible…
But system restore is definitely recommended…. Also the driver update should not be done from device manager but you should visit the Toshiba European driver page and should download the drivers from the page:
Note: both needs to be downloaded: Realtek and nVidia sound driver….
Additionally I would also recommend checking the HD audio driver driver from Realtek page directly!