我的一个网站被朋友在我的电脑上封锁了，怎样才能在internet上解除呢

工具 ---- INTERNET选项 ---- 安全 -----受限站点 ----把你的网站地址清除掉。

你说的是HOSTS被改了吧，找相应的工具重置一下就好了
记事本打开
C:\WINDOWS\system32\drivers\etc\hosts
内容修改如下
# 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