The steps to run BBM on windows are simple
1) Download Bluestack at http://www.bluestacks.com . Bluestacks is an application that enables you run android applications on windows or MAC OS.
2) Once you have it installed Bluestack open it up and click on the search button. If you have trouble installing try upgrading your Graphics card Drivers.
3) Type Whatsapp or BBM in the search button
4) click on the “search play for BBM button”. It will take you to the google play store.
5) Click on BBM and install.
6) Once you have installed you will now be able to use BBM on your PC!!!