Resolution : (For) Error code 0x80070643 or Error code 0x643 when you use the Windows Update or Microsoft Update Web sites to install updates1st try this basic one:"Start- Run- type CMDthen type MSIEXEC /UNREGISTER EnterMSIEXEC /REGSERVERif your problem not resolved yet then apply following resolution. When you try to install updates from the Windows Update Web site or the Microsoft Update Web site, you may receive one of the following error codes: Error 1 0x80070643 Error 2 0x643 This problem occurs when Windows Installer encounters an error. Error code 0x80070643 and error code 0x643 are provided by Windows Installer. These error codes are generic errors that basically state that an error was encountered by Windows Installer. RESOLUTION To troubleshoot these errors, you have to enable logging for two processes, and... To troubleshoot these errors, you have to enable logging for two processes, and then try to install the updates again. When you enable logging, the actual error codes that are generated by Windows Installer are captured. As soon as the error codes are captured, you can determine the actual issue and the resolution for that issue. These errors will require you to contact Microsoft Support to resolve the issue. However, you have to do several things before you contact Microsoft Support. To enable and collect the Windows Installer logs, follow the steps for your operating system. Microsoft Installer logging and Windows Update verbose logging For computers that are running Windows 2000, Windows XP, or Windows Server 2003 Click Start, click Run, type Notepad, and then click OK. Type the following commands in Notepad. Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer] "Logging"="voicewarmupx" "Debug"=dword:00000007 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Trace] "Flags"=dword:00000016 "Level"=dword:00000004 On the File menu, click Save As. In the Save in list, click Desktop. In the File name box, type LoggingOn.reg, click All Files in the Save as type list, and then click Save. On the desktop, double-click the LoggingOn.reg file to add the registry keys to the Windows registry. Click OK in the message box. Try to install the update again to capture the additional error information in the Windows Installer .log file. For computers that are running Windows Vista and Windows Server 2008 Click Start Collapse this image Expand this image , and then in the Start Search box, type Notepad. In the Programs list, click Notepad. Type the following commands in Notepad. Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer] "Logging"="voicewarmupx" "Debug"=dword:00000007 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Trace] "Flags"=dword:00000016 "Level"=dword:00000004 On the File menu, click Save As. In the Save in list, click Desktop. In the File name box, type LoggingOn.reg, click All Files in the Save as type list, and then click Save. On the desktop, double-click the LoggingOn.reg file to add the registry values to the Windows registry. Collapse this image Expand this image If you are prompted for an administrator password or confirmation, type the password or click Continue. Click Yes, and then click OK. Try to install the update again to capture the additional error information in the Windows Installer .log file. Step 2: Try to install updates again to create the log filesTo try to install the updates again, visit the following Microsoft Update Web site: http://update.microsoft.com/ (http://update.microsoft.com) Note It can take several minutes to collect these logs, and the update process may not seem to be functioning correctly. Allow for the necessary time for the process to finish. Step 3: Disable Microsoft Installer logging and Windows Update verbose loggingImportant As soon as Windows Update or Microsoft Update has finished, disable Windows Installer logging. Having logging enabled can require too much time every time that you install updates, can slow down your computer, and can create large log files that require large amounts of disk space. To disable Windows Installer logging, follow the steps for your operating system. For computers that are running Windows 2000, Windows XP, or Windows Server 2003 Click Start, click Run, type Notepad, and then click OK. Type the following commands in Notepad. Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer] "Logging"=- "Debug"=- [-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Trace] On the File menu, click Save As. In the Save in list, click Desktop. In the File name box, type LoggingOff.reg, click All Files in the Save as type list, and then click Save. On the desktop, double-click the LoggingOff.reg file to remove the registry values from the Windows registry. Click OK in the message box. Delete the LoggingOn.reg and LoggingOff.reg files from the desktopContact Microsoft Support for help, and reference this Microsoft Knowledge Base article when you speak to the support agent. For more information about how to contact Microsoft Support, visit the following Microsoft Web site: http://support.microsoft.com/contactus/?ws=support(http://support.microsoft.com/contactus/?ws=support) For computers that are running Windows Vista and Windows Server 2008 Click Start Collapse this image Expand this image , and then type Notepad in the Start Search box. In the Programs list, click Notepad. Type the following commands in Notepad. Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer] "Logging"=- "Debug"=- [-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Trace] In Notepad, click Save As on the File menu. In the Save in list, click Desktop. In the File name box, type LoggingOff.reg, click All Files in the Save as type list, and then click Save. On the desktop, double-click the LoggingOff.reg file to remove the registry values from the Windows registry. Collapse this image Expand this image If you are prompted for an administrator password or confirmation, type the password or click Continue. Click Yes, and then click OK. Delete the LoggingOn.reg and LoggingOff.reg files from the desktop.Contact Microsoft Support for help, and reference this Microsoft Knowledge Base article when you speak to the support agent. For more information about how to contact Microsoft Support, visit the following Microsoft Web site: http://support.microsoft.com/contactus/?ws=support(http://support.microsoft.com/contactus/?ws=support) Regards,Sohail PatelRegds,"A journey of a thousand miles begins with a single step."

Sohail,I tried to apply this resolution while installing OFFICE 2003 but no succes...Can u let me know wat would be the possible workaround for installing office 2003 patch on the mentioned error code : Error code 0x80070643