assuming that by down you mean get... ipconfig if you want all ip settings then ipconfig /all command ipconfig
If you mean to disable or turn off the ip to disconnect from the internet then ipconfig /release
the command prompt is a program where you can command the computer to perform functions such as shutdown, restart, open a certain file, start a program, etc.
Open a command prompt (Click Start > Run) then type ipconfig /all.
PROMPT command is an internal command, which is used to change the MS-DOS prompt. Through, the system displays the prompt bu default, when you start the computer.
exit
in command prompt ping -L 600 "internet address"
edit
AT
Nslookup
traceroute is usually used for this purpose.
CLS means CLear Screen. it is a command used in command prompt
start -> Run -> regedit
I personally use command prompt to map network drives using the net use command, I also use it to run chkdsk /f command (which schedules a chkdsk to run at next boot). You can use cmd prompt to move, delete files that are giving you problems. CMD prompt is very useful. Here is a page I used to open the doors of cmd prompt: http://www.amset.info/windows/dosprompt.asp