I had "personal problems" in undergrad (read: medical issue + divorce) that contributed to some poor grades, but I tried to stay away from making excuses. I took full responsibility for what I referred to as "poor decisions" that led to my taking a five-year break from school.
In my interview, my interviewer did ask why I dropped out of school. I went to a private school, so he threw out that money may have run out. I didn't want to lie, so I mentioned that i had some personal issues, including a messy divorce, but that I regretted the decision and have corrected the mistake. That was good enough - he didn't need all of the gritty details.
I can understand things like medical problems and family issues. I tried to stay away from talking about the reasons for my departure from school because I didn't want that to be the focus of my application. So I mentioned it, but I made sure that what I am doing now was at the forefront of my application.
I am of the mind that whatever caused the initial problem isn't that relevant provided enough time has passed things have occurred to establish a new track record that contradicts the previous one.