How to uninstall / completely remove Oracle 11g (client)?

• Uninstall all Oracle components using the Oracle Universal Installer (OUI).
• Run regedit.exe and delete the HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE key. This contains registry entires for all Oracle products.
• Delete any references to Oracle services left behind in the following part of the registry:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Ora* It should be pretty obvious which ones relate to Oracle.
• Reboot your machine.
• Delete the "C:\Oracle" directory, or whatever directory is your ORACLE_BASE.
• Delete the "C:\Program Files\Oracle" directory.
• Empty the contents of your "C:\temp" directory.
• Empty your recycle bin.

• Be careful when following anything listed here (above or below), as doing so may remove or damage any other Oracle-installed products.
• For 64-bit Windows (x64), you need also to delete the HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ORACLE key from the registry.
• Clean-up by removing any related shortcuts that were installed to the Start Menu.
• Clean-up environment variables:
  • Consider removing %ORACLE_HOME%.
  • Remove any paths no longer needed from %PATH%