Hi there.. I currently am trying to run 2 os on my machine. I have disc 0 running win 8 that it came with. I bought a new HDD and am trying to install win 7 on to it and every time I do it from the dvd it gets hung up during install after first reboot. I put in in another machine I have... and it loaded great but when I installed it back to my new machine it would not start up and system error came up asking to insert the win 7 disk. I tried that to but it also gets hung up while installing.. can you run win 7 on a machine or mobo that was set up with win 8... ANY HELP?