I have a stand alone LG DVD/CD R/W comb. connected to my laptop (new Drive E) because the dvd drive with the laptop is dead. I am connected by a USB Port. I can play some DVDS fine with POWERDVD 5.0 but some will not play as it states Drive E (new drive)does not recognise the format. Taking two similar dvds as an example, both having the same format, infact they are produced and manufactured from the same company, one will play fine and allow me to choose from my prompt settings how I would like to play/view it but the other when I insert it does nothing. I opened all the playing sources I have and it stated Drive E does not recognise this format. The dvds are all legitimate official releases. I have played them on the dead drive previously. Region setting is not the problem. It is only a small percentage of DVDS that will not play. It's hard to know what the criteria is for formats because some dvds have a shedfull of legends, holograms and coding. Still....

Done a recci on the net - seems this is an issue. "Unsupported disc in Drive"