1. Start -> Settings -> Control Panel -> Administrative Tools -> Services to stop all Oracle services.
2. Start -> Programs -> Oracle - OraHome81 -> Oracle Installation Products -> Universal Installer, click "Uninstall Products" - "Expand All", select all directories except "OraDb11g_home1", and delete them.
5. Run regedit, select HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE, and press the del key to delete this entry.
6. Run regedit, select HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services, scroll through the list, and delete all Oracle entries (keys starting with oracle or OraWeb).
7. Run refedit, HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application, delete all Oracle entries.
8. Delete all keys prefixed with Ora, Oracle, Orcl or EnumOra in the HKEY_CLASSES_ROOT directory.
9. Delete all keys starting with oracle in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\MenuOrder\Start Menu\Programs.
10. Delete all keys containing Oracle except the Microsoft ODBC for Oracle registry key in HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI.
11. My Computer-->Properties-->Advanced-->Environment Variables, delete the Oracle settings in the environment variables CLASSPATH and PATH.
12. From the desktop, STARTUP (startup) group, program menu, delete all groups and icons related to Oracle.
13. Delete all Oracle-related directories (if it cannot be deleted, restart the computer and then delete it), including:
1. C:\Program file\Oracle directory.
2. ORACLE_BASE directory (oracle installation directory).
3.C:\WINDOWS\system32\config\systemprofile\Oracle目录。
4.C:\Users\Administrator\Oracle或C:\Documents and Settings\Administrator\Oracle目录。
5. Delete the following files ORACLE.INI, oradim73.INI, oradim80.INI, oraodbc.ini, etc. under C:\WINDOWS.
6. If there is a [ORACLE] marked segment in the WIN.INI file under C:\WINDOWS, delete this segment.
14. If necessary, delete all Oracle-related ODBC DSNs
15. Go to the event viewer and delete the Oracle-related logs. Instructions: If there are individual DLL files that cannot be deleted, ignore them, restart, and start a new installation. When installing, select a new directory, and the installation is complete. And after restarting, the old directories and files can be deleted.
Last delete: app root directory when installing. For example, in E:\app, delete the app file in the E drive.
If you find any related Oracle services left in the view service, right-click the properties to view the "display name" of the service
run cmd
Execute sc delete "service display name"
until all related services are completely removed
If you encounter a prompt saying that the service is not installed
Then execute sc GetKeyName "Service Display Name" first
Then execute sc delete "service name obtained above"