is on the bottom of the camcorder - it *should* start with either DCR or HDR. Having a USB connection and from 2008 describes any Sony camcorder that uses either flash memory, hard disc drive, mini DVD or miniDV tape to record digital video.

In your question you ask about having to "close" the DVD in the camcorder - so thank you for the clue. Yes, you need to finalize the little DVD in the camcorder and use a new, blank, mini DVD. If you tell us the model number, we can point you at the camcorder's manual and even the page number that provides the instructions.

As for "saving the movie to your computer" for FaceBook sharing, you can rip the video from the finalized disc using a DVD ripper in your computer. I like HandBrake from www.handbrake.fr

You may have a problem with the current disc - you provided another hint, "the video will no longer play". At this point we do not know if that is a camcorder issue or a DVD issue...

As for the HTC EVO no longer saving video - it could be out of memory - but lets take one problem at a time:
1) start with the model number of the camcorder
2) get the manual
3) get the disc finalized
4) get more blank mini (8cm) DVDs for the next event...
as we decide whether the camcorder is working or not...