Impossible d'installer IE7

Bonjour,
je n'arrive pas à installer internet explorer 7
avant ca marchait très bien, je l'ai installé plusieurs fois, j'ai formaté le pc aujourd'hui et je ne sais pas pourquoi mais ça ne marche plus.
apparemment il y a un probleme avec le registre, voici le log :

0.266: 2009/01/14 18:09:29.375 (local)
0.266: h:\aee3a03c8df8af104970a213d1b8de\update\update.exe (version 6.2.29.0)
0.282: Hotfix started with following command line: /quiet /norestart /er /log:F:\WINDOWS
0.297: IECUSTOM: Scanning for proper registry permissions...
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid32
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
0.703: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.953: IECUSTOM: Scanning for proper registry permissions...
1.188: IECUSTOM: Scanning for proper registry permissions...
1.453: IECUSTOM: Unwriteable key HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.500: IECUSTOM: Backing up registry permissions...
1.516: IECUSTOM: Finished backing up registry permissions...
1.516: IECUSTOM: Setting new registry permissions...
1.547: IECUSTOM: Unable to clear DACLs HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.547: IECUSTOM: Finished setting new registry permissions...
1.547: IECUSTOM: An error occured verifying registry permissions. ERROR: 0x80070534
1.547: DoInstallation: CustomizeCall Failed: 0x3f5
1.563: IECUSTOM: Restoring registry permissions...
1.563: IECUSTOM: Finished restoring registry permissions...
1.563: Impossible d'écrire la clé du Registre de configuration.
1.563: L'installation du Internet Explorer 7 ne s'est pas terminée.
1.563: Update.exe extended error code = 0x3f5