Some games require to have admin rights to be executed correctly, to do that:
To avoid some problem regarding user rights of some folders (like Program Files / Documents…), the best thing to do is to install games in a specific folder like C:\Eroge
Since Windows Vista or 7, you have the possibility to run a program with a configuration adapted for older Windows, here is how to enable this mode:
If you have a 4K monitor or with a high resolution, this can cause issue with some games. You have an option to let the game configure the dpi setting itself.
To do so: