If PowerPoint or Excel consistently crashes when you try to open a certain file, you just discovered an unknown problem. Please, first of all, find out if the problem still occurs without think-cell being activated:
If the problem only occurs with think-cell being activated, we would appreciate you sending us the offending file, to assist us in solving the problem:
With think-cell disabled, you can load and edit the file that has been crashing. You cannot currently use the think-cell add-in with this file, but we will usually provide an update within a few days.