I've been using PD 12 with no problems for the past 2 years on my lenovo thinkpad, windows 7. And now, suddenly, all kinds of bizarre issues are happening. Overlappy sound. Some of my video is suddenly split from its audio. When I delete a clip, it often, but not always, leaves a blank/black screen split second clip in its place. Some of my clips, in the timecode under the picture window, it'll say the film time, not start at zero for the clip. But not all of them. I shot it ALL exactly the same, yet different clips react differently. What is happening?! Help! I'm editing a feature documentary and it was going so well...