Powerpoint 2007 mouse won’t click

I am trying to complete an assignment on PP2007, but my laptop will not allow me to select the font/colour that I want. Some of the fonts seem to work, but most of them I can click on them forever and they won’t work. Same for colours on the design tab. I also have problems elsewhere in the PP program persuading the mouse to click on anything I would like to select. Sometimes it will allow me to select some types of font, then a minute later I can’t.
Would appreciate some help so I can get this assignment done properly.
Thanks