Can't update Windows

Win XP, SP2. Can't update Windows through the Windows Update site. I am tyring to install Windows Defender, but get an error message stating that Windows Installer must first be installed. Attempted to install through Windows Update site, but get the following...

"The website has encountered a problem and cannot display the page you are trying to view. The options provided below might help you solve the problem." I can access the Windows Update site with no problem, but after it appears to download something, the above message appears. I manually downloaded the Windows Installer 3.x, but upon trying to install, I get an "access denied" error.

Any help would be appreciated!

 

Is there an error number? They are usually at the top-right corner, and are in hexadecimal (ie 0x8004546)

 

Sorry, yes. It's 0x8007000


Thanks!

 

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