Sounds to me like your ISP have something to do with this, I know AOL can be known for shaping connection speeds....Hence your speed being fine when they sent you to that site for the test...
Here are a few threads about AOL....
http://www.gnutellaforums.com/276256-post5.html How do I uninstall my AOL software? - Technical - AOL Help
And this one might explain the slow download speed when you tried to download another anti-virus app....AOL want you to use their security..
How to Use AOLŪ Firewall