Hi, I'm a newbie at all this so please respond with that in mind. I recently bought a computer that came with Windows 7 Professional SP 1 x64 preinstalled by the computer builders. I did not get a Windows 7 Pro install DVD with the system. The company will not supply me with one. I think this is referred to an OEM install. I am very unhappy with the way the company actually installed Win7 and want to change things to suit myself. I do have a COA sticker on the side of the computer and so, by my understanding, have a legal licence number. I also know what the OEM Product ID Number is (but I don't know how to use that). From information elsewhere in these forums I managed to download the following ISO's: Windows 7 Professional SP 1 X64 Windows 7 Professional SP 1 x64 VL (i.e. volume licence) My questions are as follows: 1) Would it possible for me to legally install Win7 Pro (and have it legally activated) to this same computer using my COA number and one of those two ISO's I downloaded? 2) If that is possible which of those ISO's should I use? Is there one that is better to use than the other (and if so why)? Or is it possible to use both of them equally well? 3) If this is possible then when and where do I have to enter the OEM Product ID Number? Or is that number already installed in the BIOS (and so I don't have to enter it at any stage)? As I'm not an expert on this please do add any other information that I should have asked for but which I don't have the experience to know to ask for. Hope my questions make sense.