Program Windows Will not Maximize

I have several windows XP computers that after a program window has been minimized it will not maximize again. It will show it the taskbar that the program is open but when you click you get nothing. I have to move the program and then it will move and I can try to maximize but it does not open any larger than this text box. I then have to close the program and then launch it again to get it to work. Has anyone else encountered this or know how to fix it?