help with login and security?

I can't login to my LJ at home. I've just discovered that I can login at work, so it must be a problem with my security settings on my home computer. Does anyone have any suggestions on how to fix this? I think it has something to do with the sites I have marked to block or allow. Do I just put in my LJ site and select "allow?" Help! I haven't been able to login since this past Sunday.