I can't seem to connect my MacBook Pro to my Wifi at home but can easily do so at other external locations. Same issue with my two other Apple desktops. But I have no connectivity issues with my other wireless devices. I currently have a total of 8 wireless devices on wifi.
Are the other devices you are using Mobile devices or Windows/Linux machines? Are you using WEP Encryption on the wireless? If using WEP, have you tried using Capital letters instead of entering in lowercase characters, and if WPA/WPA2 Encryption, checked the case of your Wireless key?
Recommend changing the wireless LAN settings from WEP to WPA-psk. PSK means pre-shared key. You can define the password to your liking instead of the random letters and numbers from WEP. Plus WPA is far more secure than WEP.
