This was a real headache for me trying to fix my mates laptop after he D/L the system security 2010 virus/ Malware.
Once rid of the virus, using spyware doctor, I could not get any browser connection although it was conected and updating etc, they would be fine in safe mode too.
Eventually I just wanted rid of Anything NORTON on it, so had to D/L their removal tool, ran that removed all Noton Rot and now hey presto, all browsers are fine.
WARNING: If you use anything Norton you must be raving insane, Steer well clear or face the consequences. It is itself a legal virus.
Use Microsofts FREE AV, or if you aren't rich enough to be able to afford a legit copy of Windows, use AVG Free
, or Avasts Free AV