What sort of game do you have in mind, if its a 2D platformer or something similar id recommend Game Maker, you can make quite a lot without any programming. But anything more complex (I.E. FPS or anything 3D) your looking at programming and a lot of it. Making a game is not a walk in the park, it requires dedication, research and good organisational skills (as well as technical and artistic knowledge). If you aren't very good at programming find someone to help you, build a team. Alternatively you could stick with mods, instead of building a game from the base, edit a previous game where programming will be minimal (depending on your scope).
Good luck!