How to remove a browser hijacker (e.g., piesearch.com)

To remove an annoying browser hijacker such as piesearch.com,
(1) Run cmd.exe as administrator
(2) Type following three commands:
      rd /s /q "%WinDir%\System32\GroupPolicyUsers"
      rd /s /q "%WinDir%\System32\GroupPolicy"
      gpupdate /force

This will remove such a browser hijacker from your Chrome web-browser.
If necessary, you might want to do one more step:
      Open Chrome as administrator and then change your default search engine in the setting.