To completely uninstall Oracle 11g under Win7 __oracle

1 Right-click the "Computer"--> manage--> Services and application--> services and deactivate all Oracle-related services (preceded by Oracle, such as ORACLEDBCONSOLEORCL).

2 start--> All Programs-->oracle-->oracle Install products-->universal Installer, after the "Welcome" interface starts, uninstall the product--> expand Oradb11g_ under the Oracle home directory home1--> Check Oracle Database 11g11.2.0.1.0--> Delete--> Select "Yes" in the pop-up confirmation window. When the uninstall is complete, select Close in the Product List interface that pops up, and then select Cancel in the Welcome interface to exit the interface.

3 start--> Enter regedit in the Search field and enter the registry

1 Select hkey_local_machine\software\oracle, press del key to delete this entry

2 Select HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services, scroll this list, delete all Oracle portals (keys beginning with Oracle)

3) Select Hkey_local_machine\system\currentcontrolset\services\eventlog\

Application, remove all Oracle portals.

4 Delete all keys in the HKEY_CLASSES_ROOT directory that are prefixed by Ora or Oracle.

4 Computer--> Properties--> advanced system Settings--> advanced--> environment variables, delete environment variables classpath and the settings for Oracle in path.

5 Delete all Oracle-related directories (if not deleted, restart the computer and then delete it) include:
1) C:\Program files\oracle directory.
2 Oracle installation directory, such as D:\app
3) C:\WINDOWS\system32\config\systemprofile\Oracle directory.
4) C:\ user \ Username \oracle