When I minimize windows they disappear? or There are no applications in my toolbar.

gnome-panel needs to be restarted. In a terminal window, type:

pkill gnome-panel

If your toolbar doesn't restart, type:

ps -ef | grep gnome-panel

In the second column, there is a number. This is the process id (pid).
 

In the terminal window, type:

kill -9 

This should restart the toolbar.