Crack WEP Using Windows: 

Many Windows users here are struggling to hack WiFi networks because most of the tutorials are based on BackTrack and other Linux Tools . Well, Here's the method to Crack WiFi networks using WEP security protocol . The WEP is a very vuarable to attacks and can be cracked easily . 

You will be using two tools:

1st  - Commview for WiFi : You will use this tool for capturing the packets sent and recieved through the Access Point you are going to hack . The more packets you capture the better chances of cracking the password . You will need more than 1,00,000 minium packets to crack the password . The packets will be captured in the .ncp format . You will use this tool to convert the .ncp to .cap .Get it from here : http://www.tamos.com/download/main/ca.php. NOTE : Some WiFi cards are supported by Commview only in Windows 7 so i suggest you install Win 7 in ur Virtual Machine if your card isnt supported . 

2nd - Aircrack-Ng GUI : You will use this tool to crack the password of the Access Point using the .cap files you obtained from the Commview application. Get it from here : http://www.aircrack-ng.org/ 
NOTE : You need to run this as administrator . Also,  Some Anti Viruses might detect Aircrack as a virus . It is a false positive . 

Step By Step Tutorial:

STEP 1 : Install CommView for WiFi . It doesnt matter whether you install it in VoIP mode or Standard mode. It automatically installs the necessary drivers . Allow it to install . Note : - You will not be able to connect to any Network using WiFi when using CommView .

STEP 2 : Click on the PLAY ICON in the Left First .

STEP 3 (Choosing the Network (a) ) : A new window should pop up now . 
Click on the START SCANNING button .

STEP 4 (Choosing the Network (b) ) : Click on the WiFi network you want to hack in the Right Coulumn and Click on CAPTURE.
NOTE : This tutorial is only for WEP protected networks .

STEP 5 (Capturing the Packets) : The windows should close now and you should see that CommView has started Capturing Packets .

STEP 6 (Saving the Packets ) : Now that the Packets are getting captured you need to Save them.

Click on Settings->Options->Memory Usage
Change Maximum Packets in buffer to 20000
Click on the LOGGING Tab .
Check AUTO-SAVING
In the Maximum Directory Size : 2000
Average Log File Size : 20

Now CommView will automatically Start Saving packets in the .ncp format at a size of 20MB each in the specified directory .

STEP 7 ( Concatenating the Logs ) : Since you are capturing a lot of logs you will need to concatenate them into one file .
To do this go to Logging and click on CONCATENATE LOGS. Choose all the files that have been saved in your specified folder and Concatenate them . Now you will have one .ncf file .

STEP 8 (Converting .ncf to .cap ) : Now that you have one file with all the packets you need to Convert it into .cap file for AIRCRACK to crack .
Click on File->Log Viewer->Load Commview Logs-> Choose the .ncf file 
Now File->Export->Wireshark/TCP dump format .

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Now, Aircrack Part :

Now for the Second Part Cracking this is very simple . Just open the Aircrack Folder->Bin->Aircrack-ng GUI.exe, and then Choose the .cap file and you should be able to do the others .

That's All, Happy Hacking !