Hi, Leah. If you look at the "version comparison" chart at
http://www.mylifeorganized.net/#comparison-table you will see the features of each version. If you select the detailed version of this chart you will see that "open/closed hours for contexts" (the feature you are trying to use) is available in the Pro version of MLO for Windows but is locked out in the Standard version. When you load the Standard version you get a 45 day trial of the Pro features; I'm guessing that your 45 days are up and the Pro features are locked. You can upgrade to Pro for an additional $30 or so, or you can continue without the upgrade but you will not have access to Pro features like context hours. If this is unclear please write back with further questions. Sorry it took so long to answer this one.