WhatsApp Messenger is a cross-platform instant messaging application for smartphones and it is available for Android, BlackBerry OS, BlackBerry 10, iOS, Series 40, Symbian (S60), and Windows Phone. In addition to text messaging, users can send each other images, video, and audio media messages.
As of now there is no official WhatsApp for Windows. So having a WhatsApp on your desktop allows you to send and receive messages. You can still use WhatsApp on your Windows XP, Vista, Windows 7 and Windows 8. Follow this tutorial on how to install WhatsApp on PC.
How to Install WhatsApp on Windows (using Bluestacks):
Step 1. The first step is to install Android emulator on Windows. There are quite a lot of them available including BlueStacks, IntelAppUp or youwave etc. For this tutorial we are using BlueStacks. You can download BlueStacks from here.
Step 2. Now install BlueStacks on your Windows.
Step 3. Once the installation is complete, open BlueStacks. Now search for WhatsApp and click Install.
Step 4: to install WhatsApp you might need a Google Account, so set it up using the on-screen instructions.
Step 5: Once installed, you need to specify your mobile number to start using WhatsApp. Once configured you can sent and receive messages on your WhatsApp account on Windows.
If you have any questions on this, please drop it in comments.