sounds randomly goes off

well,this problem has been bothering me since 5months ago when i bought it. The problem is, the sounds randomly disappeared upon startup,a red cross appeared at the volume icon, no sound device found in device manager. at 1st 2months, 2 or 3 reboot will have the sound back on but, recently, it get worse, there can be sound for few days and completely disappeared for a week..am sure theres posts regarding this issue,but no fix yet. Hoping to get good response for this.

I've done
1 reinstalling drivers(only available when the sound is on, otherewise, no device detect and thus cant install driver)
2 reinstall in safe mode
3 reformat and reinstall windows
4 system restore
5 apply microsoft fix it
6 and a lot of other things but none work