For some reason, I can't download things like directx end user runtime and mcafee. Help?

I am trying to download Mcafee, because the mcafee virus search got deleted off of my computer, and directx end-user runtime (which you get here- a href="http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=2da43d38-db71-4c1b-bc6a-9b6652cd92a3" rel="nofollow"http://www.microsoft.com/downloads/detai…/a ) because I was told it would help me with a problem in bioshock 2. I also can't update anything from mcafee, none of the automatic updates are working. i think it is a problem with a virus but I can't be sure. Help please!