Well, I just want to downgrade to W7 because W8 is a piece of shit and it has been giving me hard times and problems. I have W7 on a USB and I want to know if I need to remove all other HDD to downgrade. What I mean is that if the USB will install W7 on the HDD that has W8 without me removing the other HDD. Or do I have to remove all HDD except the one it has W8.