Uninstall Oracle

The simplest way to remove Oracle is to run the Oracle installer:

Start > Programs > Oracle Installation Products > Universal Installer

1. On the first screen click on "Deinstall Products..."
2. Expand the tree view (just so that the second level is visible) and make sure you select everything that is selectable.
3. Click on "Remove..."
4. On the confirmation screen click "Yes"
5. When it has finished click "Close" and then "Exit" to quit the installer

Whilst the Oracle installer removes many components there are a number of things that it leaves behind. In order to completely remove all traces of Oracle the following additional steps will need to be taken:

1. Stop any Oracle services that have been left running. (Start > Settings > Control Panel > Services.)
   Services which I have found left behind are 'OracleOraHome90TNSListener' and 'OracleServiceORACLE'. However there may be others depending on your installation. Look for any services with names starting with 'Oracle'.
2. Run regedit (Start > Run > Enter "regedit", click "Ok"), find and delete the following keys:
   
   HKEY_LOCAL_MACHINE
\SOFTWARE
\ORACLE

HKEY_LOCAL_MACHINE
\SYSTEM
\CurrentControlSet
\Services
\EventLog
\Application
\Oracle.oracle
   
   Note: I have had it reported that some people also have registry entries saved under HKEY_CURRENT_USER\SOFTWARE\ORACLE, this registry entry may be created by some Oracle utilities. If it exists then delete it.
3. Delete the Oracle home directory:
   "C:\Oracle"
   This will also remove your database files (unless you located them elsewhere, in which case you will need to delete them separately).
4. Delete the Oracle program Files directory:
   "C:\Program Files\Oracle"
5. Delete the Oracle programs profile directory:
   "C:\Documents and Settings\All Users\Start Menu\Programs\Oracle - OraHome90"
   if you did not first run the Oracle installer to remove Oracle then there may be other Oracle profile group directories to remove.
6. Some of the Oracle services may be left behind by the uninstall. Open ‘services’ on the control panel, make a note of which Oracle services remain and see the notes ‘How to remove a service’ to remove them.
7. If you didn't first run the Oracle Installer to remove Oracle then you may have some references to Oracle left in the path. To remove these: Start > Settings > Control Panel > System > Advanced > Environment Variables, look at both the use and system variable 'PATH' and edit them to remove any references to Oracle.