Woe For The City

Hey guys. So I've been using Cakewalk for a while no - no problems. But starting today, I've had a little problem with something - crackling. Before now this wasn't a problem. Cakewalk could run projects with lots of tracks and fxs and my cpu could handle it. But starting today, whenever I load in any midi track, even just one, Cakewalk says my CPU is at anywhere from 5-30% and starts crackling and even shutting down some times. Don't know how to fix, yall have any ideas?