I have on user on my site who the cookies do not work for. I have the cookies before the header of the script. His IE security level is set to Allow all cookies. He's tried to change the time and delete all cookies and Temporary internet files.

If it's just the one user, it's a problem their end.

Tell them to try in FireFox (to confirm it's just an IE based problem), if it still does not work it could be his firewall.

He tried it on 3 browser ie, Firefox, and psp browser. I'll ask him about an external firewall.

They client could just be an idiot...Can you show us the code your using so we can check for errors?

They could also have a program on their computer that is screwing with the cookies. I had a friend that was the only person who couldn't get on my site, cause the cookies were all screwed up. She uninstalled one of her stupid security softwares, and bam! no more cookie problem.