I want to play all the games Battlefield

In order to play all Battlefield games you will need both a  PC and Xbox360.  Battlefield 1942, Battlefield 2, Battlefield 2142, and Battlefield Vietnam are PC only releases and can be purchased for PC via Origin (I haven't seen Battlfield Vietnam there but it can still be purchased new on stores like Amazon and eBay).  Battlefield 2:  Modern Combat was a console only release and the multiplayer servers were taken down sometime around 2010.  The Bad Company series and Battlefield 3 are all available for PS3, Xbox 360 and PC and can still be purchased at most stores.