Blowing away everything in hosts won't hurt the average system using DNS servers. You may notice an unpleasant increase in junk marketing.
At this point you found the weapon but not the culprit. The original hosts file only includes comments and one entry for localhost:
Code:
# Copyright (c) 1993-1999 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
127.0.0.1 localhost
At some point you ran software that added the other host file entries, probably in an attempt to protect you from marketing or malware. That software is probably still around. So, clean up the file. Have a ball. Just remember the file, and try to think of what you may have installed that would modify it. If the software was nice then it may have left a clue about its identity up in the comment section. Compare with what I pasted above.