XFCE has worked fine until recently. Upon start of Xubuntu the mouse curser is not visible but, thanks to highlighting of icons, it is still operational. After start of a program, it becomes visible as an "x" and does not work entirely properly. I removed xubuntu-destop and installed ubuntu-desktop successfully and everything is working fine again. I thought perhaps it may have been a virus but now things are fine with ubuntu-desktop. Also, I have had problems with Firefox and the three icons on the upper right for closing the program, minimizing and reducing size, disappearing after I use the F11 key to view in full-screen. This problem has occurred very often since I started using xubuntu quite a few months ago.