If your problem is on accounts and activation maybe you just picked a bad moment for your retry. MD for reasons best known to themselves did choose to combine a peak in data traffic (people downloading Beta MD3) and new registrations with the launch of a new website that appears to be less than ready for service.

I use a 'floating' license, that is I use different computers and activate and de-activate at every session. For me this works and has worked without problems also over the last weeks. 

Experience with other 3D packages is not an advantage per se when using MD. It helps, but the approach of MD is different form the start. Experience in actual cutting and seaming of fabric may be more helpful than experience in 3D modelers.