I have a MAC OS X 10.7.5, I've installed CC on it about a month ago and now it's asking for a serial number. I don't know it anymore. Tried to find via https://licencing.adobe.com but the site won't recognise me as an Adobe user. What do I do now? I'm not that great with comps but do need CC for my work. Could anyone give me comprehensive instruction on how to deal with the problem.