I think this is going to be hit and miss trying to find and remove this infection
https://support.microsoft.com/en-us/kb/972034
follow the above link to clean host files.
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let's set browsers back to default
Instructions on how to backup your Favourites/Bookmarks and other data can be found below.
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Proceed with the reset once done.
Internet Explorer: How to reset Internet Explorer settings
Firefox:Reset Firefox
Chrome: Chrome - Reset browser settings