Well if it was a HOSTS issue you wouldn't even get to the site to see the error.
Are you sure you don't have some type of Malware on the system?
Maybe download an anti-malware scanner:
[color=green]malwarebytes.org[/color]Then install the program and do a Quick Scan not a full scan and see if it finds anything. If it does then you might want to post a new post in the Hijackthis forum for assistance.
If nothing found then take a look at your Phishing filter either from IE or from your Antivirus product and disable it at least temporarily for testing.
If no issue there then look at the firewall and temporarily disable it for testing, then turn it back on.
