Weird bugs happening on Sierra (Mac Mini late-2014)

[Allanbuzzy]

So I upgraded from El Capitan to Sierra and everything seemed okay, however when I used Chrome, Discord, etc. I noticed these slight white bars that seem to appear some parts of the page. It doesn't just happen on Chrome, it happens on most programs that use the internet.

Also, when I click and drag stuff, like for example, scrolling though a YouTube video, the cursor goes from the hand to the normal mouse. What is wrong with my Mac, is there some sort of virus I have or has something messed up my mac?

 

[Allanbuzzy]

If you think I am joking about the white bar issue, then look at this. When you visit tvforum.uk/tvhome, you scroll down to the bottom of the page, and the bar should be all blue with none of these white squares, but the page has 2 white squares:

And another page has this issue:

What do I do? I checked and despite having one virus, I scanned it and the problem of white squares still appear. What is going on?