a couple of people have said that Screen Calipers had difficulties on 64-bit Win 7. One said he solved the problem, by installing new video drivers.
For the record: I have Screen -Calipers -Compass -Protractor and -Shapes, on 64-bit Win 7, with no problems. All purchased on offers.
Notice that the key normally is a lifetime key (I upgraded from version 3 to version 4 for free), but I wonder if this fine giveaway also includes a lifetime key.