Setup failed due to unexpected circumstances. The error code is 80041002.

You see this error code in ccmsetup.log when trying to install sms advanced client.
Client.msi log also show this error: Configuration Manager Client -- Installation operation failed.

This is the result of a corrupt WMI repository on that client machine.

This work around worked for me:
1. Stop the "Windows Management Instrumentation" service.
2. Rename the %WinDir%\System32\Wbem\Repository folder to “RepositoryOld”.
3. Restart the “Windows Management Instrumentation service”.
4. Verify that the %WinDir%\System32\Wbem\Repository folder has been recreated.
5. Reinstall the SMS client software.

Failed to send HTTP request. (Error at WinHttpSendRequest: 12007)

I came across this error while installing SCCM client on a Windows 7 Machine. ccmsetup.log file was showing these errors:

Failed to send HTTP request. (Error at WinHttpSendRequest: 12002)    ccmsetup    8/18/2010 12:52:04 PM    2512 (0x09D0)
Can't connect to or retrieve file: http://smsserver/CCM_Client/ccmsetup.cab.  Will attempt a retry...    ccmsetup    8/18/2010 12:52:04 PM    2512 (0x09D0)
Next retry in 10 minute(s)...    ccmsetup    8/18/2010 12:52:04 PM    2512 (0x09D0)
Failed to send HTTP request. (Error at WinHttpSendRequest: 12002)    ccmsetup    8/18/2010 1:02:26 PM    2512 (0x09D0)
Can't connect to or retrieve file: http://smsserver/CCM_Client/ccmsetup.cab.  Will attempt a retry...    ccmsetup    8/18/2010 1:02:26 PM    2512 (0x09D0)

Solution provided at this Technet post worked for me:

-Go to IIS and expand Web Sites > CCM_Client
-Right click CCM_Client and select Permissions
-Add 'Everyone' and give them Read permissions.

SCCM Client Installation Error 80041001

While upgrading workstations from SMS client to SCCM client, you may come across this error which also indicate WMI errors in the CCMSETUP.LOG file :

"MSI: Warning 25001. Setup failed due to unexpected circumstance. The error code is 80041001"

Solution:

1. Uninstall the SCCM client by running "%WinDir%\System32\ccmsetup\ccmsetup.exe /uninstall"
2. Click on Start --> Run --> Type "services.msc" --> <enter>
3. Stop the "Windows Management Instrumentation" service
4. Open Windows Explorer and go to "%WinDir%\System32\Webem\Repository"
5. Rename the Repository folder to "OLDRepository"
6. Go back to Services.msc and start the "Windows Management Instrumentation" service
7. Install the SCCM client by either pushing the client or manually installing the client from the command line on the workstation.
8. View the "%WinDir%\System32\ccmsetup\ccmsetup.log" file to make sure the client installs as requested.
9. Verify the "%WinDir%\System32\Webem\Repository" folder was created.

How to uninstall SCCM 2007 client

Option 1: Run ccmsetup.exe /uninstall command

Option 2: Download  SCCM Client Center from http://smsclictr.sourceforge.net/ and use that program to remotely uninstall client from computers.