I just did a search and it seems there is another hosts file dropped in the %SystemRoot%\help folder and it sets that as the default hosts file.

Have you run the Symantec cleaner yet? It should reset all this back to the default values and delete the files:

http://securityresponse.symantec.com/avcenter/venc/data/trojan.qhosts.removal.tool.html

Gareth