It sounds like Explorer (the Windows shell) has crashed, probably caused by something like those DVD programs you mentioned crashing earlier. Programs can sometimes get stuck in an endless loop if something goes wrong during an important step, then Windows just switches between programs in endless loops and nothing happens.
You probably won't be able to salvage this
I recommend saving your work regularly. Don't work on something for hours and then save it. Save every 5 minutes and shit like that.