You need to create a bootable usb. You can use poweriso but you'd need to get an iso file of the os you want on your computer to create the image. Google "create bootable usb using poweriso"and you should find detailed walkthroughs.
Yes. You can do it through the USB. You can find instructional online for it. Simply look up "USB BOOT (And the os you want)" Just be aware that if you are trying to reset your laptop to factory defaults then you are not trying to format it. The two things are different.