If you facing problems trying to uninstall Oracle from your Windows workstation, or unable to uninstall Oracle installations cleanly and properly, the following steps may be used to uninstall all Oracle products currently install on the workstation:

Warning: Editing registry may cause problems to your PC.

  1. Uninstall all Oracle components using the Oracle Universal Installer (OUI).
  2. Delete the HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE key which contains registry entries for all Oracle products by using regedit.
  3. Delete any references to Oracle services/components in the following registry location: HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/. Looks for key entries that starts with “Ora” which are obviously related to Oracle.
  4. Reboot the workstation.
  5. Delete the ORACLE_BASE directory. (i.e C:\Oracle)
  6. Delete the C:\Program Files\Oracle directory.
  7. Empty the temp directory.
  8. Empty the recycle bin.

With this, the computer is more or less clear of any Oracle components, which allows you to reinstall Oracle if needed.