Read this information and follow the directions carefully:
http://malektips.com/spyware_adware_0017.html
Make sure to make that one backup:
Open file "HOSTS" in Notepad. Before making changes, do a "Save As" and save a backup of this file as "HOSTS.BAK". Then reopen the HOSTS file.
Save that file to your Desktop for easy access.
Now, delete all entries in this file except for the following and any other entries you are sure have legitimate uses:
127.0.0.1 localhost
Now everything in the hosts file should be gone except for 127.0.0.1 localhost.
Thanks
http://www.dslreports.com/faq/10131
http://www.michaelhorowitz.com/sample.hosts.file.txt