Graphics bugged

Hello people, i have a bug..
When i was on Windows 8.1 everything was working very well, now i switched to Windows 10, and when i'm in game on screen where i type my username and pw and while in game, the upper half of the screen somehow flashes, like when your graphic card is old and bugged, but mine isn't.
How can i fix that?
Here is how it flashes, like the flashlight: https://giphy.com/gifs/flashlight-dgZ4QM4HHyXZe
Also the texture bugs a little bit, but only on upper part of the screen..
Thanks
Regards

I Can post video on www.sendspace.com if you guys want.. I just need an answer :)

One week has passed, still no reply. Thanks staff. Good job

what client, Wotlk, cata or Mop ?

Why would the staff help you to fix your computer?

My bedroom door creaks a little, i am still waiting for a GM to come and help me out.

You could have gotten some help from the 'community' if you had provided even the most basic of info other than saying:
- Windows / graphics bugged / link to a completely unrelated flashlight gif.

You could have spent the past 7 days looking for a solution which 100% likely is out there for your particular problem yourself.