Hi CNiall,
The account you're using to log into these forums does not seem to have any registrations attached to it. Perhaps did you register/order your games under a different email address? If so, this would be the root of your problem, a very common one.
You can visit https://www.stardock.com/support/ and enter some other email addresses of yours to see if one of them receives the serial numbers you are looking for. You can then register those serial numbers manually in Impulse, or create an Impulse account under that email address and use it to log into Impulse instead. We recommend the latter course of action because it's easier.
Hope that helps! If you need more help, reply to this thread or drop us an email, sales@stardock.com.