To completely uninstall oracle11g, follow these steps:

To completely uninstall oracle11g, follow these steps:
To completely uninstall oracle11g:
1. Choose "start"> "Settings"> "Control Panel"> "Administrative Tools"> "services" to stop all Oracle services.
2. Start-> Program-> Oracle-OraHome81-> Oracle Installation Products-> Universal Installer, and click "Uninstall product"-"Expand All ", select all directories except "OraDb11g_home1" and delete them.
5. Run regedit, select HKEY_LOCAL_MACHINE \ SOFTWARE \ ORACLE, and press del to delete the entry.
6. Run regedit and 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 to 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 Oracle settings in the environment variables CLASSPATH and PATH.
12. Delete all groups and icons related to Oracle from the desktop, STARTUP group, and program menu.
13. Delete All Oracle-related directories (if the directories cannot be deleted, restart the computer and delete the directories again:
1. C: \ Program file \ Oracle directory.
2. ORACLE_BASE directory (oracle installation directory ).
3. C: \ WINDOWS \ system32 \ config \ systemprofile \ Oracle directory.
4. C: \ Users \ Administrator \ Oracle or C: \ Documents and Settings \ Administrator \ Oracle directory.
5. C: \ Delete the following files in WINDOWS: ORACLE. INI, oradim73.INI, oradim80.INI, oraodbc. ini, and so on.
6. C: \ if the WINDOWS. ini file contains a [ORACLE] Tag segment, delete the segment.
14. If necessary, delete all Oracle-related ODBC DSN
15. Delete Oracle-related logs in Event Viewer: if some DLL files cannot be deleted, restart and start a new installation, select a new directory. After installation and restart, the old directory and files can be deleted.