My recommendation is to run Spybot, updated, first and then install the new HOSTS file.
The MVPS HOSTS file was recently updated [April-02-2013]
Download: hosts.zip (138 kb)
How To: Download and Extract the HOSTS file
HOSTS File - Frequently Asked Questions
Note: the "text" version makes a great resource for determining possible unwanted connections ...
http://winhelp2002.mvps.org/hosts.txt (563 kb)
Get notified when the MVPS HOSTS file is updatedhttp://winhelp2002.mvps.org/updates.htm