Uninstall an oracle database

Windows Registry Editor Version 5.00[-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleOraDb11g_home1TNSListener][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleMTSRecoveryService][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleJobSchedulerXE][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Oracle11][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Oracle Data Provider for .NET][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleXETNSListener][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleXEClrAgent][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleServiceXE][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\Oracle.xe][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\Oracle Services for MTS][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\Oracle.VSSWriter.ORCL][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\OracleDBConsoleorcl][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\Oracle.orcl][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleServiceORCL][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleVssWriterORCL][-HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE][-HKEY_CLASSES_ROOT\OracleHome.OracleHome][-HKEY_CLASSES_ROOT\OracleDatabase.OracleDatabase.1][-HKEY_CLASSES_ROOT\OraPerfMon.OraPerfMon][-HKEY_CLASSES_ROOT\OracleDatabase.OracleDatabase][-HKEY_CLASSES_ROOT\OracleConfig.OracleConfig.1][-HKEY_CLASSES_ROOT\ORAMMCPMON11.ComponentData.1][-HKEY_CLASSES_ROOT\OraPerfMon.OraPerfMon.1][-HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE][-HKEY_CLASSES_ROOT\ORCLMMC.About][-HKEY_CLASSES_ROOT\ORCLMMC.About.1][-HKEY_CLASSES_ROOT\ORCLSSO.ComponentData][-HKEY_CLASSES_ROOT\ORCLSSO.ComponentData.1][-HKEY_CLASSES_ROOT\OracleConfig.OracleConfig][-HKEY_CLASSES_ROOT\OraOLEDB.Oracle.1][-HKEY_CLASSES_ROOT\OraOLEDB.Oracle][-HKEY_CLASSES_ROOT\OraOLEDB.ErrorLookup.1][-HKEY_CLASSES_ROOT\OraOLEDB.ErrorLookup][-HKEY_CLASSES_ROOT\ORAMMCPMON11.ComponentData][-HKEY_CLASSES_ROOT\ORAMMCCFG11.ComponentData.1][-HKEY_CLASSES_ROOT\ORAMMCCFG11.ComponentData][-HKEY_CLASSES_ROOT\ORADC.ORADCCtrl.1][-HKEY_CLASSES_ROOT\OracleProcess.OracleProcess.1][-HKEY_CLASSES_ROOT\OracleProcess.OracleProcess][-HKEY_CLASSES_ROOT\OracleInProcServer.XOraSession.5][-HKEY_CLASSES_ROOT\OracleInProcServer.XOraSession][-HKEY_CLASSES_ROOT\OracleInProcServer.XOraServer.5][-HKEY_CLASSES_ROOT\OracleInProcServer.XOraServer][-HKEY_CLASSES_ROOT\OracleHome.OracleHome.1][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleOraDb11g_home2TNSListener][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleJobSchedulerORCL][-HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\OracleDBConsoleorcl][-HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE]

Run the registration file and delete the corresponding oracle path in the system variable.