Left Button doing Right Click in Windows

I have a Dell Inspiron 15 3567 (laptop) running Windows 10. It has a touchpad. Everything was fine until I formatted (reinstalled windows on) it. After that, I rebooted first time and was surprised to see that simply tapping on touchpad does right-click. Clicking on touchpad also do Right-Click. Left button on touchpad also do right-click, BUT Right button on touchpad does left-click? Why is the action inverted, and how do I fix it?
What I have tried (None of those worked):

• Installing Drivers for touchpad.
• Uninstalling and re-installing touchpad driver.
• Rebooting the PC, trying out from another user.
• Checking online for solutions.
  

And What I haven't tried:

• Connecting external mouse.
• Checking in another OS (live boot).

And because its a touchpad, it is really hard to control such device, Can anybody help me?

Solution 1:

You need to change a setting in Windows:

1. Open Settings ( win + I )
2. Devices --> Mouse
3. Open Additional Mouse settings
4. Here, toggle from Left-Handed to Right-handed.