Also try this:
Go in safe mode.
Run your anti-malware (av and anti-spyware). Schedule a boot-time scan of your Spybot.
Replace your hosts file with a good one as mentioned above. (which you appear to have have done)
Run CCleaner portable lite version (available on Majorgeeks) and use it.
Open IE > Internet Options > Security tab. Check in Trusted Sites/ Local Intranet/ Restricted sites, if you see any entries - delete them.
You could also try ZonedOut utility to Add, Delete, Import, Export, Build a Black/WhiteList of websites . It includes Restricted, Trusted and Intranet Zones. It is an excellent too just 185kb.
Best to always create a system restore point before making any changes to the system.