Hiya,
I didn't have to give a presentation (or even an interview, damn my uni seems so easy compared to elsewhere!), but I would definitely use Powerpoint if I had to. Gives you something to focus on, looks really professional, gives you a chance to show off your presenting/lecturing skills, and I personally think that it makes presenting so much easier! For 5 minutes though, try to keep the number of slides/text on them to a minimum - just key points. :-)
Good luck with it - hope you get it. xx