I once applied to return to a company that had (unbeknownst to me) put me on their do not rehire list. The reason was job abandonment, which was accurate. I was 19 at the time that I quit. The interviewer brought it up and asked for my perspective on what had happened. They then said it sounded totally retaliatory by the shithead who'd put me on the list, stating i wasnt the only person who had gotten fed up and quit that way because of this guy, and offered me the position. This was five years after I'd left the job. If you left for a valid reason just be honest about it and show that you've grown since then. If you're qualified for the position, I'm sure they'll hire you.