Acer M5-481T WebCam and Sound issue!!

i bought Acer M5-481t with windows 7 pre installed .but after updation from windows 7 to windows 8 >>8.1>>10 webcam of my PC never seems to working . i tried many way to fix this even i did fresh windows installation but still webcam is not working.

At the startup of camera app,it works for few second but soon the error comes "WEBCAM NOT connected".

2nd issue is with my audio driver/hardware(i don't know). sometime after booting my PC,audio device doesn't work and i have to reboot my pc saveral time to fix this or need to reinstall whole drivers sometime.

There is a red cross on my speaker icon and error is "No Audio Device Found". this problem starts frm some few days ago in windows 8.1 and is still there in windows 10 also.