Internet Explorer 6 --- A Pain in the Neck

[Sandcrab]

I have Windows XP (SP2) with Norton Antivirus 2003, Webroot's Window Washer & Spy Sweeper. Also Adaware Plus & connect to the Internet via a broadband router\hardware firewall. I also use the free Zonealarm.
Every now & again, Internet Explorer refuses to connect to the Internet even though all is ok with all the above. No address appears in the Address Bar & the 'The Page Cannot be Displayed' appears instead of my Home Page. Running the Windows System File Checker then rebooting temporarily fixes the problem (after a 20 minute or so wait). Is there a fix available or will I have to re-install Windows to correct this?