How do I install KB2446708 Security Update when my computer says Error details: Code 66A?

I have tried several times to install Security Update KB2446708. Each time, it fails and says Error details: Code 66A

I am running Windows Vista 6.0 with Internet Explorer 9.

how can I remove personal security trojan from my computer?

I am unable to access control panel and I can not download any programs to get rid of it. Microsoft security essentials will not download. I am running xp professional. I can not afford to have it fixed professionally as I have already dumped money into it that I can’t use.

How do I remove McAfee Internet Security from my computer?

I have already deleted It off my computer, but it still gives me this screen. for everything except google chrome http://img3.imageshack.us/img3/9462/anoyying.png

What else can I get for my computer’s Security?

Currently I’m using cc cleaner, spy bot, adaware, malwarebytes, spywareblaster and an systemantic(spelling) anti virus. What else can I get I recently got that security suite virus and I wondering do i need more protection.