怎样知道一台电脑是否能够连接互联网?

运行CMD，在提示符下输入 :ping www.baidu.com
如果运行结果是 timed is out 表示不能上网,如果显示:
Reply form.........time<.. TTL=...则表示可以上网！

可以用命令ipconfig,也可以用ping来测试

程序－运行－cmd-PING一下外网地址或网站
如：ping 222.154.154.132
ping www.baidu.com
如果返回显示
C:\Documents and Settings\Administrator>ping www.baidu.com

Pinging www.a.shifen.com [220.181.18.155] with 32 bytes of data

Reply from 220.181.18.155: bytes=32 time=204ms TTL=52
Reply from 220.181.18.155: bytes=32 time=130ms TTL=52
Reply from 220.181.18.155: bytes=32 time=181ms TTL=52
Reply from 220.181.18.155: bytes=32 time=218ms TTL=52

Ping statistics for 220.181.18.155:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 130ms, Maximum = 218ms, Average = 183ms