Oracle reinstallation report SID already exists

Oracle reinstallation reports that SID already exists. 1. Choose "start"> "Settings"> "Control Panel"> "Administrative Tools"> "services" to stop all Oracle services. 2. Start-> Program-> Oracle-OraHome81-> Oracle Installation Products-> Universal Installer uninstalls all Oracle Products, but the Universal Installer itself cannot be deleted. 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. 7. Run regedit, HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Eventlog/Application to delete all Oracle entries. 8. Choose "start"> "Settings"> "Control Panel"> "system"> "advanced"> "environment variable" to delete the Oracle settings in the environment variables CLASSPATH and PATH. 9. Start from the desktop and STARTUP (START) in the group and Program menu, delete all Oracle-related groups and icons 10, delete/Program Files/Oracle directory 11, and restart the computer, after the restart, you can delete the Oracle directory 12 and Oracle-related files. Select the default Oracle directory C:/Oracle and delete the portal directory and all subdirectories, and delete the following file ORACLE from the Windows 2000 directory (generally C:/WINNT. INI, oradim73.INI, oradim80.INI, oraodbc. ini and so on. 13. WIN. if the INI file contains a [ORACLE] Tag segment, delete the segment 14. If necessary, delete all Oracle-related odbc dsn 15. In the event viewer, delete Oracle-related log descriptions: if some DLL files cannot be deleted, restart and start a new installation. select a new directory during installation, old directories and files can be deleted.