Lets isolate the problem.
First, check first the sound settings, if the icon can not be clicked or can not be moved moved from minimum to maximum then there is a last thing you can do since you already tried reinstalling the sound driver and it will not work anyway. Have your OS fixed, or in other terms, reinstall your OS. Wondering why did this happen? A simple virus can cause this.
Second, isolate again, try to use a headset, if your headset is doing fine and the sound settings are normal then it is a hardware problem, consult the manufacturer or any local technician.
And lastly like the second one, if headset is okay but soundsettings are abnormal or you can't change it, then format the laptop.