What is a tactful way to approach an issue with a roommate?

Take her and the rest of your other roomates to a nice resturant and discuss the issue calmly and quitley. Comfront her with her bad behaviour and ask her what has been troubeling her (nicely). Either she will spill everything out to you and your other roomates and have an emotional breakdown or she will start yelling at you and what not. If she reacts the first way, consoul her and try your best to figure out a solution. If she reacts the second way, well, at least you have your other roomates to back you up and tell her what she needs to do. And also, at least you can say " I tried in the best way I possibly could have". In the end it boils down to you and what you decide to do, but this is one suggjestion. :) P.S. I have gone through these kinds of problems at school. This is a good solution.