First make sure all updates are applied, then try this in IE:
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. Security tab
6. Reset all 4 security zones to Default
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. Privacy
6. Restore 1 Default button
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. Advanced
6. Restore 1 Default button
You may need to do the following as well
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. General tab
6. Remove cookies, temporary files and history
Kudos to Raptor and Fed
Are you sure you are virus/spyware free? If not, have a read:
http://www.computerhope.com/cgi-bin/yabb/YaBB.cgi?num=1149948530 If that doesn't get it, consider uninstalling Norton, at least until this is resolved.