Yoga 2 Pro Easycam not working

[YOUCEF]

HELLO
I have yoga 2 PRO the problem withe web cam not working all
some times just the led light on
the problem all come after I updet from 8 TO 8.1 AND SAME PROBLEM WITHE 10
NOW I BACK TO WINDOWS 8.1
I TRAY ALL SOLLUTION UPDATE WEB CAM DRIVERS FROM LENOVO WEB SITE AND UPDATE SHIPEST MORE MORE
whene I see on net I see more have same problem
I put my problem in forums microsoft and forum lenovo but no solution