"Locking" prior year returns in a dual-monitor setup.

I'm working with a dual-monitor system for the first time this year. I prepare 2007 returns with the same client's 2006 return open on my second (identical) monitor. Because the two programs show forms with almost identical appearances, I've caught myself a number of times accidentally entering 2007 data into 2006 returns.I have converted all 2006 files to read-only, which prevents me from saving altered returns. But I'm wondering, is there a way to "lock" the prior year's data entry screens, so that it becomes impossible to enter any data into the return in the first place? Or, if not, is there a way to colorize, or change the data font, or otherwise change the appearance of the prior year forms screens as a constant reminder that it's not a 2007 return?Thanks,Chuck Warman, CPAWichita Falls, TX