Glad it worked, it's a little mistake I've made a few times in the past myself
As Chef mentions, the drag-and-drop thing in Windows Explorer is packet writing, and a lot of us won't recommend it as packet writing can be unreliable (even using packet-writing software such as Nero InCD, Roxio Drag to Disc etc).
When I need to use a disc like a HDD and just drag stuff to it at my leisure, I use DVD-RAM discs. The discs themselves are a lot more reliable too. Your LG supports these so it may be worth giving them a go rather than packet-writing (or multi-session, which I find can often be equally problematic).