Overlaying problems

[Otto]

Well, I've managed to create a working overlay that doesn't crash when resolution changes, but my problem is that I can't get it working with most of full-screen games. Actually only Torque-powered games have so far worked and even they only when running on DirectX (With OpenGL they don't). Even any of 2d games don't work, neither my own C++ games.

Anyways, for this overlay I'm using the example shown at http://www.gamedev.net/community/forums/topic.asp?topic_id=367591 (Managed DirectX, C#).
My OS is Windows Vista Home Premium (Yes, I have disabled Aero effects to get it working).

Thanks for any help!

EDIT: Whoops, I forgot, this is a C++ forum! Even tough I'm using C# this time, just post in C++.net or pure C++, I'll get it from that. ;) The original sample (in C++) is here: http://www.gamedev.net/community/forums/topic.asp?topic_id=359319