Internet Explorer 7 : Impossible d'installer!

J'ai fait 5 tentatives d'installer le navigateur Internet Explorer 7, mais
sans succès. J'ai suivi toutes les directives à propos de ce genre de
problème; il y avait 5 étapes pour tout régler : on devait regarder dans le
fichier ie7.log afin de cerner le problème. Mais rien n'y fait; j'ai pas
réussi. J'ai fouillé tant bien que mal toutes les pages de support sur ce
sujet, et encore là, je n'ai trouvé aucune réponse.

Alors voilà le contenu de mon fichier ie7.log
Est-ce que quelqu'un pourrait m'aider?
Merci à l'avance.
-

[ie7.log]
0.547:
0.547: 2006/11/03 08:02:02.984 (local)
0.547: z:\3eb896a78a844437c37cb53b00424f\update\update.exe (version 6.2.29.0)
0.579: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
3.110: IECUSTOM: Scanning for proper registry permissions
3.344: IECUSTOM: Unwriteable key HKCR\.application
3.719: IECUSTOM: Scanning for proper registry permissions
3.985: IECUSTOM: Scanning for proper registry permissions
4.204: IECUSTOM: Unwriteable key HKCR\.application
4.297: IECUSTOM: Backing up registry permissions
4.329: IECUSTOM: Finished backing up registry permissions
4.329: IECUSTOM: Setting new registry permissions
4.360: IECUSTOM: Unable to clear DACLs HKCR\.application
4.360: IECUSTOM: Finished setting new registry permissions
4.360: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
4.360: DoInstallation: CustomizeCall Failed: 0x3f5
4.391: IECUSTOM: Restoring registry permissions
4.391: IECUSTOM: Finished restoring registry permissions
4.407: Impossible d'écrire la clé du Registre de configuration.
4.438: L'installation du Internet Explorer 7 ne s'est pas terminée.
4.438: Update.exe extended error code = 0x3f5
0.469:
0.469: 2006/11/30 02:12:08.296 (local)
0.469: z:\277808766655633d018a82dcf3b035e1\update\update.exe (version
6.2.29.0)
0.688: Failed To Enable SE_SHUTDOWN_PRIVILEGE
0.688: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
2.688: IECUSTOM: Scanning for proper registry permissions
2.969: IECUSTOM: Unwriteable key HKCR\.application
3.906: IECUSTOM: Scanning for proper registry permissions
4.219: IECUSTOM: Scanning for proper registry permissions
4.453: IECUSTOM: Unwriteable key HKCR\.application
4.625: IECUSTOM: Backing up registry permissions
4.750: IECUSTOM: Finished backing up registry permissions
4.750: IECUSTOM: Setting new registry permissions
4.781: IECUSTOM: Unable to clear DACLs HKCR\.application
4.781: IECUSTOM: Finished setting new registry permissions
4.781: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
4.781: DoInstallation: CustomizeCall Failed: 0x3f5
4.828: IECUSTOM: Restoring registry permissions
4.922: IECUSTOM: Finished restoring registry permissions
4.969: Impossible d'écrire la clé du Registre de configuration.
5.031: L'installation du Internet Explorer 7 ne s'est pas terminée.
5.031: Update.exe extended error code = 0x3f5
0.579:
0.579: 2006/12/22 22:43:03.156 (local)
0.579: z:\e764ee538270800554b3e5e329059cc4\update\update.exe (version
6.2.29.0)
0.594: Failed To Enable SE_SHUTDOWN_PRIVILEGE
0.594: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
2.625: IECUSTOM: Scanning for proper registry permissions
2.860: IECUSTOM: Unwriteable key HKCR\.application
3.485: IECUSTOM: Scanning for proper registry permissions
3.750: IECUSTOM: Scanning for proper registry permissions
3.985: IECUSTOM: Unwriteable key HKCR\.application
4.079: IECUSTOM: Backing up registry permissions
4.110: IECUSTOM: Finished backing up registry permissions
4.110: IECUSTOM: Setting new registry permissions
4.125: IECUSTOM: Unable to clear DACLs HKCR\.application
4.125: IECUSTOM: Finished setting new registry permissions
4.125: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
4.125: DoInstallation: CustomizeCall Failed: 0x3f5
4.157: IECUSTOM: Restoring registry permissions
4.157: IECUSTOM: Finished restoring registry permissions
4.188: Impossible d'écrire la clé du Registre de configuration.
4.219: L'installation du Internet Explorer 7 ne s'est pas terminée.
4.219: Update.exe extended error code = 0x3f5
0.359:
0.375: 2006/12/23 08:27:48.000 (local)
0.375: z:\761007d48d9f1439d6413fe872b38a\update\update.exe (version 6.2.29.0)
0.469: Failed To Enable SE_SHUTDOWN_PRIVILEGE
0.469: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
1.797: IECUSTOM: Scanning for proper registry permissions
2.031: IECUSTOM: Unwriteable key HKCR\.application
2.422: IECUSTOM: Scanning for proper registry permissions
2.656: IECUSTOM: Scanning for proper registry permissions
2.875: IECUSTOM: Unwriteable key HKCR\.application
2.969: IECUSTOM: Backing up registry permissions
3.047: IECUSTOM: Finished backing up registry permissions
3.047: IECUSTOM: Setting new registry permissions
3.078: IECUSTOM: Unable to clear DACLs HKCR\.application
3.078: IECUSTOM: Finished setting new registry permissions
3.078: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
3.078: DoInstallation: CustomizeCall Failed: 0x3f5
3.094: IECUSTOM: Restoring registry permissions
3.094: IECUSTOM: Finished restoring registry permissions
3.141: Impossible d'écrire la clé du Registre de configuration.
3.187: L'installation du Internet Explorer 7 ne s'est pas terminée.
3.187: Update.exe extended error code = 0x3f5
0.454:
0.469: 2007/01/07 09:29:02.796 (local)
0.469: z:\0b3ae64be9728f2e0e0b40ba\update\update.exe (version 6.2.29.0)
0.500: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
1.969: IECUSTOM: Scanning for proper registry permissions
2.204: IECUSTOM: Unwriteable key HKCR\.application
2.594: IECUSTOM: Scanning for proper registry permissions
2.829: IECUSTOM: Scanning for proper registry permissions
3.047: IECUSTOM: Unwriteable key HKCR\.application
3.125: IECUSTOM: Backing up registry permissions
3.204: IECUSTOM: Finished backing up registry permissions
3.204: IECUSTOM: Setting new registry permissions
3.219: IECUSTOM: Unable to clear DACLs HKCR\.application
3.219: IECUSTOM: Finished setting new registry permissions
3.219: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
3.219: DoInstallation: CustomizeCall Failed: 0x3f5
3.219: IECUSTOM: Restoring registry permissions
3.219: IECUSTOM: Finished restoring registry permissions
3.266: Impossible d'écrire la clé du Registre de configuration.
3.297: L'installation du Internet Explorer 7 ne s'est pas terminée.
3.297: Update.exe extended error code = 0x3f5