To dump your WiFi password on Windows, you need a program like WiFi Password Dump. You can get the latest 7.0 version for free from this site. This software by SecurityXploded is available for free download. It is also classified as belonging in the Antivirus category, specifically Personal Security. However, it is recommended to use this software only for Windows operating system, because it may cause some security risks if used on other operating systems.
You need to download a free version of WiFi Password Dump onto your computer and then follow the instructions. For Windows vista systems, simply follow the prompts for installation. Then, place the WiFi Password Dumps HTML file into the program folder of your Windows Vista PC. Now, this should be all you need to do to permanently recover your forgotten password.
For windows operating systems that are not supported by the Windows Vista software, such as XP, you will need to use the Windows password recovery program that is included with your Windows installation CD. For Windows vista systems, all you will have to do is click Start > All Programs > Accessories > System Tools and then look for the option "WD Mode." You should then click on this option and run the Windows password recovery program, or the offline Windows password recovery program, as explained here. Finally, you will have to repeat this step in order to reset the passwords on your WiFi enabled computers.