This offer is now dead.
Clairol just posted this on their Facebook page: "Foam fans, you spoke and we heard you—because some of you were unable to participate last week, we’re giving away another 10,000 FREE boxes of NEW Nice ‘n Easy Color Blend Foam! Check the NEW Foam tab at the top of this page TODAY, February 2 at 9PM EST to claim yours".
So go their page and "like" them. Be there a few minutes before 9pm and then refresh the page right at 9pm. I believe you will then follow the instructions to get your coupon. This site will probably be slammed so I'm not sure what kind of chance you will have, so I wouldn't stress too much about it. BUT it is worth a shot if you're already on the computer.