HiCustomerand thanks for choosing Just Answer. My name is XXXXX XXXXX I will be happy to assist you with this question.
If you currently have a Windows computer on the wireless network, you can download the WirelessKeyView program from here:
Just download and run the program to see your key. If that doesn't work or if you don't have another computer on the wireless network, please let me know the make/model of your wireless router and I will tell you how to find it manually.