If it's happening after the raw image is made, then I'd check the compositing tab... did you make any changes there?

well I didnt change anything at all. Now thats the smaller problem, I cant hit render button, last image I tired still uploading, yellow status in mecabricks (10th render try, did it yesterday half past 9)

Think my problem is video card or driver related, but I am really beginner

Mecabricks does the renders on its own server. So this will have nothing to do with your computer. You will achieve the same results using a phone, ipad, low-spec laptop or high-end desktop. As long as you have browser access to Mecabricks, the end result will be the same. If there is an issue with the render, then it will either be in the data that you give the renderer or an issue with the render server itself.

How are you lighting the scene? Are you using lamps, HDRI, or a combination of both?

its alright, I have done it perfectly - had to change a few things at compositing; funny, because I thought that default setting make my picture as it is, anyway, thank You

long live Mecabricks