I had purchased Sony Laptop with Windows7 Professional pre-installed. It did not come with Windows discovery/re-installation CD. During a recent malfunctioning of the laptop, I ended up re-partioned the hard drive and in the process deleted the partition that holds Windows 7 recovery/reinstallation files. I tried to purchase a new CD from Sony but they claim they don't have it? At the bottom of my laptop, there is windows 7 professional product key code. Currently, I am running Windows XP professional that I had previously purchased as a retail package. My question is: If I install a trial version of Windows 7 Professional, do you think the Windows7 product key that came with the laptop will work? or OEM Windows7 keys do not work with retail version? Any help will be greatly appreciated.