Microsoft Windows updates fail to install properly?

A required system file is not registered correctly.

Resolution: Re-register Windows Update DLLs.

1. Create a restore point and a proper backup of your system.
A proper backup is always a good idea before modifying any portion of the operating system.To learn how to create a system restore point to backup the registry and settings, click here.

2. Open the Windows Command Prompt:
CLICK Start, CLICK Run, TYPE (omit quotes): "cmd" and CLICK "ok".

3. Stop the Windows Automatic Update Service:
TYPE (omit quotes): "net stop wuauserv".

4. PRESS "enter" and Click "ok" on the verification message that you receive.

5. Register the Windows Update DLLs:
TYPE (omit quotes): "regsvr32 regsvr32 %windir%\system32\wuapi.dll".

6. PRESS "enter" and Click "ok" on the verification message that you receive.

Repeat steps 5 and 6 for the following Windows Update DLLs
"regsvr32 regsvr32 %windir%\system32\wuaueng1.dll"
"regsvr32 regsvr32 %windir%\system32\wuaueng.dll"
"regsvr32 regsvr32 %windir%\system32\wucltui.dll"
"regsvr32 regsvr32 %windir%\system32\wups2.dll"
"regsvr32 regsvr32 %windir%\system32\wups.dll"
"regsvr32 regsvr32 %windir%\system32\wuweb.dll"

7. Start the Windows Automatic Updates service:
TYPE (omit comma): "net start wuauserv".

8. Exit the command prompt:
TYPE (omit quotes): "exit" and then PRESS "enter".

9. Attempt to run Windows Update.