xnumad

Sadly, the usual uninstallers of those programs DO NOT remove their "enforcement of pre-installing" extensions into Google Chrome web browser. ("Another program on your computer added an extension that may change the way Chrome works.")
This guidance only contains instructions for Google Chrome.

Enter about://extensions into the adress bar of Google Chrome.
Click on "Details" for the respective extension you want to stop from being pre-installed.
Copy the extension ID from the URL (the text after "id=").
Now remove all these in the registry existing keys at the following paths:
  - HKEY_LOCAL_MACHINE\SOFTWARE\Google\Chrome\Extensions\<id>
  - HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Google\Chrome\Extensions\<id>
  - HKEY_CURRENT_USER\SOFTWARE\Google\Chrome\Extensions\<id>