Hi Donovan,
This should be easy with conditional formatting. Put conditional formatting on the step2 checkbox that "Disables this control" if "step1" "is equal to" "FALSE".
Do the same for the step3 checkbox, but check to see if the step2 is FALSE.
Note that you only have to check the previous steps check box because if it is true then it is assumed that the checkboxes above it are true.
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge