Just thought i'd pass along some info regarding problems with disks that are written but are not finalized.
I have hard you can use DVD Decrypter to close the disk but have tried but gotten no results using the close disc tab.
when I clicked on close track. Then click on close session and then click on close disc it worked and have been able to now open DVD's in PC or other DVDs players
So far has worked on 2 different dvd's I have had problems opening and this was on 2 different P'C's using 2 different burning programs.
Hope this helps!