why doesn't my computer connect to airport and my phone and ipad do?

Hi Alex Paulson,

Welcome to the Apple Support Communities!

If you are having an issue with your Apple computer connecting to your Wi-Fi network, I suggest working through the troubleshooting steps listed in the attached article.

Wi-Fi: How to troubleshoot Wi-Fi connectivity

http://support.apple.com/kb/HT4628

Have a great day,

Joe