I need a dual boot setup. I have a new 320 GB SATA hard drive and I need to replace an old 80 GB hard drive. I have a Windows XP Home disc that came with the machine and the Windows 7 Professional Upgrade disc. What do I need to do in order to have a painless dual boot setup. I want to be able to choose before the system starts booting. Please help and thank you very much for your time.