Delete Oracle registry-uninstall Oracle

The uninstallation program that comes with Oracle cannot fundamentally uninstall Oracle, which leaves a hidden danger for the next installation. How can we completely uninstall oracle?
To clear the Registry directly, follow these steps:

1. Start-> Settings-> Control Panel-> management tools-> services
Stop all Oracle services.

2. Start-> Program-> Oracle-orahome81-> Oracle Installation products->
Universal Installer
Unmount all Oracle products, but the universal installer cannot be deleted.

5. Run regedit, select HKEY_LOCAL_MACHINE \ SOFTWARE \ oracle, and press del to delete the entry.

6. Run regedit, select HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services, and scroll
Delete all Oracle entries.

7. Run refedit,
HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Eventlog \ application,
Delete all Oracle entries.

8. Start-> set-> Control Panel-> system-> advanced-> environment variable
Delete Oracle settings in the environment variables classpath and Path

9. Delete all groups and icons related to Oracle from the desktop, startup group, and program menu.

10. Delete \ Program Files \ oracle directory

11. restart the computer to completely delete the Oracle directory.

12. Delete Oracle-related files, and select the default Oracle directory c: \ oracle.
And delete the following files from the Windows 2000 directory (generally c: \ WINNT ).
Oracle. ini, oradim73.ini, oradim80.ini, oraodbc. ini, and so on.

13. If the [Oracle] Tag segment exists in the win. ini file, delete it.

14. If necessary, delete all Oracle-related ODBC DSN

15. In Event Viewer, delete Oracle-related logs.

Note:
If some DLL files cannot be deleted, You can restart and start a new installation,
During installation, select a new directory. After the installation is completed and restarted, the old directory and files can be deleted.