为什么我今天无缘无故首页变成了4199上网导航http://www.4199.com/的了，改也改不掉

首先找到hosts表，hosts 表的位置：C:\WINNT\system32\drivers\etc ，用记事本打开依次将文件打开（一定用记事本打开），可以看到的以下为正常，如果被改到 125.91.1.20 那就是中了4199了。只要是hosts表里的文件连接到这个IP的都删除(125.91.1.20)！

# 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

其次是查找users.dll 文件