can't re-install net framework assistant for firefox

i ve removed the net framework assistant for firefox extension which was alread disabled by following the "METHOD 2" procedures in the following link:
http://support.microsoft.com/kb/963707

but now i'm having some issues with firefox and i have my doubts that it might be the reason of those issues.

windows update service offered me to install "update to net framework 3.5 service pack 1 for the net framework assistant 1.0" and i did install it, but windows keeps offering it again and again, as if it was never installed.
i ve downloaded the update itself and manually installed it, but still no avail.

how can i revert things back?
p.s.: system restore is disabled and i cant restore an image right now. i need an alternative solution.

thanks

 

thank you so much, ronjor.
i ve carefully read the posts in that link and i ve noticed that i had described my problem in a wrong way in my previous post.
aamof, i can install the update, i don't get any error messages, the update is installed successfuly, but windows keeps offering me the same update again and again, as if it was never installed. though the relevant update is listed in windows' add-remove programs list.
i know that sometimes windows does this, but nod32 is warning me about this very same update as missing, too. that s what makes me wonder what it's all about.
thanks again.

 

thank you, ronjor.
the repair tool in the link you provided solved the issue.
thanks again