Can you change motherboards or hard drives and still access the program?

Of course, you can.

DVDFab doesn't check any hardware info, so you can even transfer it to a brand new pc.

Just make sure that you have your registration key saved somewhere that you can access it after making your hardware changes.

Maybe the installation file too, although you could always just download the latest release of it.

Come to think of it, there's also a procedure for retrieving a lost registration key, as long as you know which e-mail address you used when you purchased the product, but it's probably easier to just not lose the key in the first place.

Great advice. Most of us have learned to back up important data...especially regkeys! I keep mine on a floppy, a system hdd clone as well as another nifty method which is to email it to yourself. As James said, the auto retrieval link on Fengtao's site works well (within seconds...depending on your connection).
http://www.dvdfab.com/retrieveregkey.htm