Is it a credible mac address?? If you're just pulling numbers and letters out of your butt, then it's not going to work. The mac has to have a valid oui. Something like this, changed to will work. The first three pairs, , means it's a linksys card. The last three is the unique card id, , these are the numbers you want to change. Using something like most likely won't work. Most wireless routers know the difference between real, and made up numbers.