it sounds like your virus protection has expired and you may have a firewall up blocking the internet connection.
two options: pay mcafee the yearly renewal or go here
http://www.download.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html?part=dl-10044820&subj=dl&tag=button&cdlPid=11009475
and download a free professional antivirus, anti-spyware, and extensive firewall.
if you do download the new FREE program, make sure you completely uninstall ALL virus and spyware programs you may already have installed. Including Mcafee.
after youve decided what you will do and finished that part. open your web browser, go to internet options, advanced, and reset to default settings. then select the security tab and set to normal.
you should be all set!! Good Luck