Signus is an old game which wasn’t ready for powerful 3D graphic cards to come and is not backwards compatible with newer operation systems than Windows XP. Thus the present-day machines can run it only with difficulties. Two ways are known, a short one, and a long one.
Shorter way: DxWnd
Thanks to an Italian enthusiast nicknamed ghotik, there is a utility DxWnd available at Sourceforge. Using it, Signus can be launched in a windowed mode on contemporary computers with Windows 10. Even though I have minimum experience with it, I recommend trying it. It makes the game run completely without a problem, with all the videos and gorgeous graphics. The main and unquestionable advantage of DxWnd is, that the lenghty, difficult, and disk space demanding virtualization of old Windows is not necessary.
I also recommend reading the discussion focused on Signus.
How Signus runs using DxWnd, is demonstrated by RealPsojed in his short YouTube video.
Longer way: Operation system virtualization
If, for any reason, you don’t want to use DxWnd, you have to take path of the whole operation system virtualization. Moreover, it’s not enough to just install the OS, you also have to install all the necessary drivers (the graphic one above all).
There are several virtualization programs, my personal experience is based on these: Microsoft Virtual PC 2007, Hyper-V and Oracle’s VirtualBox.
Virtual PC 2007
If you haven’t switched to Windows 10, Virtual PC is a rational choice. It’s a Microsoft program, so the support of older virtual Windows is guaranteed. Full funcionality is provided by Virtual Machine Additionals, which are installed to the OS directly via the program.
Since Windows 10 came, there also came necessity of an alternative to Virtual PC mentioned above, because it cannot be installed in the new system. The first possible substitute is Hyper-V, also by Microsoft. Although I couldn’t find the virtual drivers directly in it, I had to look for them on the Internet and install them manually. Yet I had no success even after that. In my experience, the virtual system gained not only the graphic driver, but also many new, unknown devices without any drivers. And Signus had a problem with it.
According to information I acquired on the Internet on the topic, Hyper-V is not primarily meant to be used with old systems like Windows XP. So if you want to stick to Microsoft application even in Windows 10 zůstat, I don’t see many options.
Oracle’s VirtualBox still remains reliable virtualization tool. To get Signus to run correctly, you make it do with basic settings and virtual drivers included in built-in Guest Additions. The program can also work with VHD virtual disk format, used by Microsoft programs, which might make the migration e.g. from Virtual PC a lot easier.
Migration from Virtual PC elsewhere
If you were used to Virtual PC in older Windows and you want to play Signus e.g. via VirtualBox, there’s a problem you might come across. It’s the Virtual Machine Additionals function mentioned above. If it’s installed, it causes conflict of drivers, and therefore absolute keyboard inoperability. Then the Additionals have to be uninstalled. Yet it’s only possible via Virtual PC itself. So if you have just Windows 10, without any chance of running Virtual PC, you will most certainly have to install Windows XP anew.