From what I have seen on the websites, the DK Encyclopedia of Nature is compatible with Windows 7. You must have been using the wrong settings and because of that, the software refuses to work. Firstly, if you have the application installed, remove it completely then perform a re-installation. Right click the software and choose Properties > Compatibility. From the drop down menu, select Windows XP. There is also a Run as Administrator option on that window. Tick it and then apply the changes. Launch the program and it should work.