My laptop can't roll over links?

On the website for my school work, there are a lot of roll over links. It's like there will be a word that's blue instead of black and when you roll your mouse over it a box will come up with the definition or some fact that has to do with the lesson. For some reason my laptop can't do it? Nothing happens when I roll over them. This is kind of a problem since I need to know the definitions of the words in order for the rest of the lesson to make sense.... I could look up each word but that's veeeerrryyy tedious and some of the definitions they give are much more helpful than the internet can find because they work with the context of the lesson. Does that make sense? Anyway, I really can't figure out why it doesn't work but it's only on my laptop. So, does anyone know what the problem is and how to fix it?