Where would be a good place to start for researching the Medieval Times were/were not the 'Dark Ages' topic?
A great place to start with research is New Advent's page reproducing the Catholic Encyclopedia's article on the Middle Ages, found
here. This is a great resource to use as a "home base" of sorts.
Should your student wish to explore any element of the Middle Ages in more detail, the article links out into various other articles about topics such as Gothic Architecture and Liturgical Music, and others. Articles also tend to quote and cite professionals, so further research can proceed from there.