Do a search for files over a certain size, 500mb should do it. I'm not on windows at the moment, but it's in the usual search place. Start->Search->Search Options and select Size. Put in a size like 500000kb and click Search now. Look for something called VTS****.VOB, that will probably be the temporary files. If that isn't there (which may happen if it got as far as generating an image), you should see something in a temp directory somewhere.