to solve it;)


right click, you will see the context menu(i mean, the edge...)


then click the last area if it, and the window for adjusting the setting for ur desktop is out


notice that the first tag is Theme.

and by default it is highlighted in the drop down menu of the choice of theme, so now you press up or down , then enter

it will work.


notice: sometimes, if you press up , it may come out a IE window, then you press down instead

good luck