Screen lag

LuboBG - Morai

i was thinking was from my pc but got him cleaned from dust and still same.
I let game on without touching anything and then game becomes laggy like there is many people
but there isen't,when i move the mouse lag stops so what's the problem?

SylenThunder - Twilight Temple

I will need a copy of the output from a dxdiag.txt file, and a link to a published Speccy report taken while you are having the issues.
(Remember to use the [code] tags for the dxdiag info and to remove any trademark characters so it doesn't get cut off.) (CODE tag is the # symbol in the editor.)

Also, here's a couple of interesting articles...
Lag vs FPS
How to get rid of Lag guide.