i did try, but i can't find a solution or something :'(

1 - after i did the Graphics Card Drivers updates(even with Windows Update), why, on videos frames, i get, by some seconds, 90% black color(like the image)... like i said after update. i don't know why these happens.. maybe someone can explain more about it.
Name:  videos error.png
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(after update the Sound Card Drivers, i lose the sound.... so i use the previous drivers)

2 - comparing between the batery and cable... the CPU perfomance can be less if i use the batery?