nopuedo instalar internet explorer 7

no puedo instalarlo y he realizado segun la pagina de errores que tengo en el
escritorio, todas las opciones. Tengo el siguiente reporte del ie7:
0.391: 2009/01/03 02:26:26.968 (local)
0.391: c:\43969e49820913890fa39505\update\update.exe (version 6.2.29.0)
0.422: Failed To Enable SE_SHUTDOWN_PRIVILEGE
0.422: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
0.422: IECUSTOM: Scanning for proper registry permissions...
0.782: IECUSTOM: Unwriteable key HKCR\.application
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid32
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
1.454: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
2.391: IECUSTOM: Scanning for proper registry permissions...
2.735: IECUSTOM: Scanning for proper registry permissions...
3.063: IECUSTOM: Unwriteable key HKCR\.application
3.250: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
3.438: IECUSTOM: Backing up registry permissions...
3.485: IECUSTOM: Finished backing up registry permissions...
3.485: IECUSTOM: Setting new registry permissions...
3.500: IECUSTOM: Unable to clear DACLs
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
3.500: IECUSTOM: Finished setting new registry permissions...
3.500: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
3.500: DoInstallation: CustomizeCall Failed: 0x3f5
3.500: IECUSTOM: Restoring registry permissions...
3.547: IECUSTOM: Finished restoring registry permissions...
3.579: No se puede escribir la clave del Registro de configuraciones.
3.579: La instalación de Internet Explorer 7 no ha finalizado.
3.579: Update.exe extended error code = 0x3f5

gracias