I've been using Vegas Movie Studio for a long time and I have always had this box area that previews what I'm looking at of the video I'm editing with the play cursor, but it's gone now. I can't edit videos now cause I can't see the preview of the video or anything and it's really frustrating. Please help.
So you obviously have Movie Studio 13 (or Platinum in Simple Edit mode, change to Advanced if you have that version). The reset (my link has the advice, follow closely) usually helps in the basic Movie Studio. Check your version before you try the reset, Platinum should be OK going back to default layout.