So, I was just browsing facebook when I started doing something away from the computer. When I came back and refreshed, it suddenly told me

Blocked by URL Filter Database
Your requested URL has been blocked by the URL Filter database module of McAfee Web GATEWAY. The URL is listed in categories that are not allowed by your administrator at this time.
URL: http://de-de.facebook.com/
URL Categories: Social Networking
Reputation: Minimal Risk
Media Type:
Rule Name: BLOCK URLs Whose Category Is in Category BlockList

and

For assistance, please contact your system administrator. 


That would be no problem at all, if there weren't a few PROBLEMS with that.

1. I don't have McAfee installed. I searched with the Microsoft search, I looked through my programs in the system control - nada.
2. I AM the system admin. I owned this PC for a few years now, always been the admin. My anti virus program is Avira. The computer had McAfee pre-installed, but I uninstalled it right after I installed Avira a few years ago.
3. It mainly blocks social networking sites like tumblr, facebook and twitter, but also the McAfee site. What.
4. It's only "installed" on Firefox. I tried accessing tumblr with IE (yes I still have it installed ugh) and it works just fine.

So. Help? Disable Avira and scan your PC with Microsoft Security Essentials, see what turns up.Thanks, I will, as SOON as Avira finished checking for viruses (which will take a while longer...)