Help, Net Use to shutdown remote

I need help using the Net Use command. I am attempting to shutdown another computer remotely. My peer to peer network consist's of 2 laptops, both running Windows XP Pro, both connected to a Linksys router, one of them wirelessly, the other through ethernet. The command I will use is " net use * \\***.***.***.***.\c$ ". It will then tell me the password is incorrect, and to type in the password. However, there is no password that I have set for the computer. For those of you who can't tell, I am a newbie, and I'm in school for programming and networking. My teacher showed us this trick, but I just cant get it to work. I did play with it and eventually got it to map the drive. I did that by typing in " net use * \\***.***.***.***\c ". So then when I went to use the shutdown command...." shutdown -s -m \\***.***.***.*** " , it simply told me access denied. Please help. Thanks.