Problem with 1024x768 resolution

[placyd]

I've started a new game in AGS 3.1.1 and I've set up a 1024x768 resolution, but when I want to test the game an error message pops up: "There was a problem initializing graphics mode 1024x768. Problem: Failed to create Direct3D Device".
I've tried to change both color depth and default grapics driver, but I got the same error.
What can be the problem?

[SSH]

What resolution is your screen, and are you playing in a window or full-screen?

[placyd]

Ok, that was the problem. My screen is 1024x768, and I've only tried to test in a window, as I use to 
Thank you!