but i totally have no experience on any image editor software any guide that i can follow?
maybe what i have describe in my first post is not clear, what i wanted is something like this video http://www.youtube.com/watch?v=ATB9kpW4Uuk but i want erase the foreground
exactly like this but in photoimpact , i have really no experience any web for me to learn
If you follow the instructions given in the video you'll notice that first the foreground is selected (the dog) and later the selection is inversed in order to select the background (everything except the dog). Just skip this "inverse step" and you'll still work with foreground.
Check the features in your tool. If Photoimpact is an picture editor than you should be able to do the same (maybe the menu steps are slightly different).
A good alternative for Photoshop is GIMP - Open Source and you can download it for free at www.gimp.org. They also have lots of tutorials. But I think you better head down to the library and get some books about digital pictures and digital editing. Without knowing the basics it's very difficult to understand what is happening.