With a bit of time and effort, you can make your own computer games! If you don't believe me, go to YoYoGames.com and see the many games created by people just like you, many of them with no or limited programming skills. All it takes is some practice and you can make a great computer game! So why not get started? Here are some tools you can use:

Game Maker is one of my favorite computer programs. What's so amazing about it is that you don't even need to have any programming skills to be able to make good computer games. And besides that, it's completely free. It's not just a demo or trial version, and you're even free to make your games into executable files that anyone can play without having Game Maker on their computer, and sell them!
Game Maker was designed by Mark Overmars, originally as an animation program, and then he remade it into a computer game design program. He recently partnered with YoYo Games and released version 7.0. Game Maker is very easy to use, and you can make almost any kind of game with it. A great help is that it has a very good documentation and tutorials that can help you get started very easily. The official Game Maker website is at http://www.yoyogames.com.
After you're acquainted with their easy drag-and-drop interface for game making, you can also learn programming skills with Game Maker's simple and intuitive GML language, and be able to do even more! You can get even more features by upgrading Game Maker for a small fee, but using the free version by no means limits your creativity and flexibility. You can still make amazing games for free, but you do get a few extra options in the paid version.
I greatly recommend Game Maker for anyone at all who is interested in creating computer games.

Adventure Maker is another great game creation program. It's main use is for point-and-click adventures, and it does it well! It's very easy to use and, though limited in the free version, you can get acquainted with making Myst-style games and applications. It also packages several other useful tools with the game creation program.
You can also make games for PSPs, as well as Windows computers. You can only play the games you make using the free version if you have Adventure Maker on your computer, so it's not really suitable for making games to give or sell. They have two paid versions, for commercial or non-commercial use.
The Adventure Maker website is at http://www.adventuremaker.com. You can go there for more information about features.