block people using my wifi freely

guys,
i had my own wireless set in my shop,and i already set in the password to prevent somebdy else using it freely,but recently one 'friend' of mine come and ask for the password,unable to refuse,i simply gave him my key,and now he using it,FOR FREE!!!
i dont mind sharing my wireless but atleast he shuld help me to pay but when i ask him to,he simply said,that is not mine,so he dont have right to pay..

so is there any solution to block him from using my wifi freely without changing my old password,because if i change it he sure will come back and i'm not sure i can refuse to give him another password..i check his computer name using my cmd on net view,but i dont even know how to block him..any help and response will be appreciate,and sory for my bad english.

beg.

Obviously he's no friend or he wouldn't be taking advantage of you.

You'll have to change your wireless password and you also need to password-protect your computer so that he can't get access to it.

As for not being able to refuse him, just hold a knife to his throat and tell him he's having no more free rides on your wireless network. If he persists, report him to your ISP.

knife?i got my gun..
i realy dont want to change my password dude,maybe i shuld just shut off my modem and let both of us cant access internet..lol
thanx for reply seavixen32..:)

oreo27,
i try and let you know soon..
thanx.

Alternatively, you could set up an access list on your router (if it supported) so that only known MAC addresses can connect to the network if you know how to do that ?

ibshaw,
i am watching youtube to learn it now lol..
thanx in advance.

B E G said:

knife?i got my gun..
i realy dont want to change my password dude,maybe i shuld just shut off my modem and let both of us cant access internet..lol
thanx for reply seavixen32..:)

Gun is good! :)