Well, luckily or unfortunately I dunno, but from what I know about computers, that problem can be due to a number of things - some easy to fix, some taking a little more effort.
First, go to Internet Explorer's toolbar, and select "Tools". From the "Tools" menu, click "Internet Options". On the "General" tab, delete temporary files, history, and cookies. Next, click the "Security" tab, and then click "Trusted Sites". Click "Sites", then click
to clear the checkbox labled "Require server verification (https:) for all sites in this zone". In the "Add this Web site to the zone" dialog box, type or paste the following URLs, clicking "Add" after you enter each:
Code: http://update.microsoft.com
http://download.windowsupdate.microsoft.com
http://update.microsoft.com/microsoftupdate/v6/default.aspx
Click "OK" twice then "Apply" to exit back to Windows, reboot, then, before trying to update
turn off/disable your resident security/privacy software (antivirus, antispyware, add/popup blockers, firewall, that sorta thing) and see what happens when you try to update. If no joy, try the following, one at a time, in order, rebooting after each, and see if anything helps.
If and as necessary, and only if and as necessary, step trough these possible fixes in order, running the suggested fix, rebooting, then revisiting
Microsoft Update[/i][/b] to see what happens. If you're successful at any point, you're done - skip the rest.
Fix 1) - Go to Start>Run, type, without the quotes, "cmd", click "OK" or hit [ENTER], then at the blinking prompt in the black box that opens, type, without the quotes, "regsvr32 wuauserv.dll" , hit [ENTER] - you should get a message saying either "successful" or "could not ... ". Either way, at the blinking prompt, type, without the quotes, "exit" and hit [ENTER] to close the command prompt and return to Windows. If you received a "success" message, reboot and see what happens when you try to update. If you received a failure message, or if you still can't update, move to fix 2.
Fix 2) Perhaps some services and/or required for running Windows Update service for whatever reason no longer are running or registered correctly with Windows.
This should stop the services, re-register the files used and restart the necessary services.
Open Notepad or your preferred text editor (its really best to use Notepad for this, though). Copy&Paste the following into it - exactly as below:
%windir%\system32\net.exe stop bits
%windir%\system32\net.exe stop wuauserv
%windir%\system32\regsvr32.exe %windir%\system32\atl.dll
%windir%\system32\regsvr32.exe %windir%\system32\jscript.dll
%windir%\system32\regsvr32.exe %windir%\system32\msxml3.dll
%windir%\system32\regsvr32.exe %windir%\system32\softpub.dll
%windir%\system32\regsvr32.exe %windir%\system32\wuapi.dll
%windir%\system32\regsvr32.exe %windir%\system32\wuaueng.dll
%windir%\system32\regsvr32.exe %windir%\system32\wuaueng1.dll
%windir%\system32\regsvr32.exe %windir%\system32\wucltui.dll
%windir%\system32\regsvr32.exe %windir%\system32\wups.dll
%windir%\system32\regsvr32.exe %windir%\system32\wuweb.dll
%windir%\system32\net.exe start bits
%windir%\system32\net.exe start wuauserv
Then "Save as ... ", naming the file "WUREPAIR.CMD" (be sure to
include the quotes in the filename - don't save the file as a "TXT" file), to your Desktop or some folder you can easily find and access. Locate the saved file, double-click it to run it (confirm if prompted). Reboot, and see what happens when you try to update. If still no joy, move to Fix 3
Fix 3) Download and install, per instructions on the page, the latest version of
Microsoft XML Parser (MSXML) 3.0 Service Pack 5 (SP5)
When that has downloaded and installed, reboot, and see what happens when you try to update.
Done correctly, one of those 3 will handle about 95% of Update Failure errors of the sort you reported; the 1st fix works about half the time, the 2nd fix, if necessary (ie - the 1st fix didn't help) works about a third of the time, and the 3rd fix, if necessary, works mosta the rest of the time. Lemme know how you're getting along - if you're still having troubles, mebbe we can go at this from another angle.