CompuServe Messages

Dear Jonas, I have a slight problem with 3D Studio, and I was hoping you might be able to help me. It has happened twice now, and the one time it practicly ruined my life. I am a student at the Art Institute of Pittsburgh, and I had to do a project using 3D Studio. We had 11 weeks to finish the project. Anyways I was just finishing up a minute and a half animation the night before it was due. I finished it up, and decided to take a break. I saved the file and turned off my computer. About an hour later I came back to my computer to render the animation, and when I tried to load up the file, I recieved a message stating that it was an Invalid 3ds file. Everything was gone, I checked the backup that was made during a hold operation, and recieved the same message. Unfortunately that was the only backup. My teacher was kind enough not to fail me in the class. Then just the other day, the same exact thing happened, only that the backup was not corrupted, and I was able to save the project. Do you know why this happened twice? Thank you very much. Chris Wynn