Why won't the Bold, Italic and Underline features work when I click on them as I write?

I just got my first lap top to use when I am working on my book. I transfered what I had written so far off the other computer I had used previously. I need to use the features I have mentioned, but they won't respond when I click on them. Everything else works except for those. I use a free word processor, and this one happens to be Tiny Word. Does this make a difference?