Hi. I have a Dell Dimension 9150 with a 3.2gig Dual core processor and 4x 1gig ram. I am currently running Win 7 32bit on a 320gig hard drive. I have a second 500gig hard drive installed. I am toying with upgrading to 64bit and as a test I would like to install either Win 7 or 8.1 64bit on the second drive. In doing so will I be able to choose which system to boot into at start up and possibly retain both systems, please?