My old Win 7 Acer laptop bit the dust, so I've removed the HDD and installed it in a (USB) external HDD enclosure. I can now access the content there from my current laptop (Lenovo G500 Win 8.1). I would l like to boot into that old OS without sticking it in my new lappy. I tried to by going to recovery settings and then advanced startup and choosing USB, but that didn't work. It said something about that it wasn't bootable, and then it booted from my internal drive. Can this be done, or is it not really doable?