You deal with a lost device just as in a common app. A screensaver is nothing more than a app with special defined parameters.

As Endurion says, a screensaver is an executable Windows PE like any other. Moreover, nobody writes tutorials on lost devices. Read your API documentation to see why the device may not be behaving correctly. If you still can't work it out, post us some details and code and we'll see what we can do.

Admiral

Most tutorials cover lost devices.

Basically, when the screen saver takes effect, your Direct3D calls will fail because the device is lost. Your program will not know about this failing until you call the Present method. The Present call will return an error indicating lost device.

When you detect a lost device, you have to reset or recreate your Direct3D resources (textures, vertex/index buffers, etc). The Direct3D device needs to be reset. For textures, if they are in managed memory, you don't have to worry about them. If they are in default memory, you will have to reload them.

Hope that helps. If you need more info, search for tutorials that talk about lost devices.