Can't go to any websites except e-mail

need some advice

 

I have 6 users on onlinefamily.norton

 

Web Setup - 3 can only access preset sites; 3 are monitor only for the web

 

On one computer that is monitor only, we can not not access the web on any user except for two e-mail sites: https://mail.fairview.org & and gmail login

  • the tab opens with the web address shown, but all you get is a blank page, no error message
  • sometimes the web address has some extra coding after the normal address, sometimes it does not
  • when I take onlinefamily.norton off get my web access back
  • I reloaded onlinefamily.norton and for an hour was able to access the web on all 6 users, but the next mornining when we restarted the computer and logged in again, we had the same problem

 My other 2 computers can access the web with all 6 users

 

specs on the effected computer

  • windows XP professional v 5.1
  • firefox v 3.6.3
  • Avast virus software - the rest have AVG

Any thoughts on solving this