2 os on 2 seperate hard drives
 

I have 2 different hard drives on my VAIO VGCRA840G Desktop. One is the original media center that I had problems with and installed the 2nd hard drive with windows 7. They both work perfect but to switch I have to shut down and switch wiring to the other hard disk. How can I leave both plugged in and switch OS on reboot?:confused: