I suspect that simply uninstalling Windows Defender won't fix the problem,
but it is certainly an easy thing to try--so go ahead.
Another knowledgable user here has recommended this application:
http://wiki.djlizard.net/Dial-a-fix
for help with some similar issues.
I don't have any experience with it, but some others I know have looked at
it and had relatively minor critiques.
You might want to cautiously try it out.
Alternatively, if you attempt to go to WindowsUpdate, record what error
messages you get.
Additionally, look at the windowsupdate.log text file in \windows, and read
the entries related to that attempt, and record the error numbers involved.
(if the log is not in English, I won't be able to make much sense out of it,
but the error numbers should be the same.) And either research these
numbers yourself, via either support.microsoft.com or google or both--or
post them back here, and I can see what I can find on them.
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