You can use Whatsapp while you are on a PC. If you Update your Whatsapp through the Playstore open in your App "Web Whatsapp" and go to web.whatsapp.com and scan the QR Code which is visible on the Site and you can chat through your Browser! :D But remember: Everything you will send through the Browser, will go through your phone, so make sure your Phone is connected to your Wi-fi.
It is currently only working, if you have Android on your Smartphone.