kali live:
             if you have low end pc you don't whats to use vm ware so you can boot kali linux in usb or dvd i will show the video down if you need help. in live booting there is no any loss of your window os data. but the data which you will save  in kali live will not be remain saved.

SEE THIS VIDEO FOR LIVE BOOT FROM USB



virtual machine:
                                   virtual machine is only good for high end pc and not much batter in low end pc
if you whats to download virual machine see my previous post  introducing vm ware