Texture changing color after render

Hello.
Ive loaded a 24bit BMP file to my program then im making a texture of it. But the problems is that the colors changes alittle on it when i have 32bit colors as resolution in windows. It’s working fine with 16bit, except that im getting damn low fps.

Here’s a picture to demonstrate:
http://img81.imageshack.us/img81/9703/cpdampde4.png

Also, here’s the code that im using:
http://nopaste.php-q.net/231803

Yours,
GriZzm0

Found the problem by myself.

3D settings in the gfx drivers was set on performance.