Hi, I bought a laptop which came with a copy of Office Professional Plus pre-installed. The seller didn't give me the product key, but of course it's easy enough to get. The up shot is that I can now use this key to install the retail version on my desktop, which activates ok. Obviously I'm attracted to the possibility of a free product key, but will this affect the seller's copy and are there any other downsides? e.g. limited number of installs or key blacklisted