Vista - Trouble loading page

When on a website and I try to access some feature on it I get "The
connection was reset" The connection to the server was reset while the page
was loading. It follows with 3 possibles, Site unavailable, check computer
network connection or If using a firewall or proxy be sure that Firefox is
permitted to access website. So far I usually have this trouble on Gamefly,
the "Rent It" key never loads so I can't use the function and also if I'm on
a site like, MyFamily, and I want to answer someone's post I get the same
message which of course tells me to Try Again. I'm using Vista Home Premium
and my browser is Firefox Mozilla and I'm connected through a cable modem
network.