Help me waste time on the internet
So, I am doing an internet puzzle-riddle-thing. I could look for spoilers, but I am being virtuous and only asking for technical help. There is a 10-second sound clip that makes no sense, but there have been enough Beatles references that I wonder if I should try playing it backward. Can someone tell me how to reverse an MP3 on a not-very-souped-up Vista machine, please?