The Oracle Installer creates a new ORACLE entry in the Windows registry. This Oracle registry contains configuration parameters that control such things as the name of the Oracle home directory, the location of the product preference file, and the location of the help files.
You can view and optionally edit the Microsoft Windows Registry by using the Registry Editor. This editor is located in the directory where your Windows software is installed. To start the editor, choose Start | Run, then type REGEDIT and click OK.
In the Registry Editor, expand the HKEY_LOCAL_MACHINE node, then expand the SOFTWARE node. Click the ORACLE key to display the Oracle configuration parameters.
You can modify any parameter value by double-clicking the parameter name to display the Edit String dialog. Change the value in the Value data text box, then click OK to accept the new value.