I have Lenovo IdeaPad z510 laptop with windows 10 (upgraded from 8.1).
For a few months (or more?) I have a problem with my touchpad:

In some situations it doesn't work at all. Sometimes it works just fine. And sometimes it's so fast that I can't control what it's doing. And it's not always the same speed. And sometimes the faster I try to scroll the slower it actually goes.

Note: I use 2-finger scroll.

Google Chrome:
It seems to work just fine, but sometimes (witout any obvious pattern other than that when it happens - it happend everytime I try) when the window is out of focus or when I scroll with just the right speed - it goes uncontrollably fast. And when it does that - the faster I try to scroll the slower it goes (I will later describe it as faster=slower)

Netbeans/all java programs:
Works only when the window is not in focus. And sometimes too fast. And faster=slower

Doesn't work at all

Windows CMD window:
Way too fast to do anything. Even with 10000 lines (max) it's so fast that I can't measure the faster=slower effect.

Explorer.exe, Edge browser:
These work fine

What may be possibly wrong and how to fix it!?

I'm 100% sure it's fixable because it works correctly on linux.