InstallAware

Is there a way to gray out a check box within the MSI code?

I have not tried to see if it work like you are wanting it to but you might try this. Set the check button Option Enabled = False
and then in the code set the variable that the check box writes to to be true before the dialog comes up.

It's really quite simple;

Add a label control to your form, set the visible property to false, set the caption property to a variable, in your script where you determine if the check box should be enabled or diabled set the caption property variable to either true or false. In the dialog double click the label control, in the object rules tab/page set the appropriate rules to enable and disbale the check box based on the value of the label caption.