I don't know why!!
In this windows, there are two bars: 1 is the "Applications"/"Actions" which is located at the bottom of the screen 2 is the one which is loacted at the top of the screen.
I put the top bar right on top of the bottom one. And now every time I minimize a program/a browser/ or any thing, I can't retrieve them back because they don't show on any of the bars. In fact, the one that I moved from top to bottom shows nothing. Before it at least has an option which allow you to minimize/maxmize all the programs which are running.

I remember I encoutered a problem, so I askes me a question and I click some button. then every time I boot I end up like this. I am using fedora 3.

It seems you'r using Gnome (the default desktop) and I think there's a possibility you somehow missed the taskbar thingie. U need to add it to the panel or whatever its named.

okay, solved thank you

You can also use Alt+Tab to switch between active programs. Saves time sometimes if you only have a small number of windows open.

oh, great!! thank you