In general, Photodex is very easy to work with. As far as having it on two machines, see if this addresses your question:
http://kb.photodex.com/2133/can-i-insta ... -computer/You should not have to buy a new copy to move it to a different machine either - drop them an email or call them if you have any questions/issues - unlike many companies these days, they not only answer emails but have a support staff that can actually answer questions and help !!
mikey