Problem with my Hoover UH70055 bagless vacuum - roller won't spin?

Don't have the manual any more, it's pretty new, got it from target, but threw out box. was just vacuuming the floor, and rolled over a cord, and the roller stopped spinning. Nothing is stuck in it, it moves if I flick it, but the vacuum isn't spinning it, only suction, but no roller spinning, so it's pretty useless for vacuuming. Any ideas on what might be wrong?