hosts文件被我删空了怎么办

hosts 文件在C:\WINDOWS\system32\drivers\etc下。
它的作用是在你访问网络时提供快捷的ip地址，不用再从dns解析ip。而且你可以将不访问或遭到攻击的病毒网站的域名屏蔽调，让自己不会再访问屏蔽的网址。
如果没有了可以用360急救回复，或者自己手动建立一个文件。文件名 hosts
内容为
# 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

其实不写也没关系。