If you can open it; audit, purge, audit, purge. Do other house cleaning on the drawing.
If you can't open it; try recover.
If it opens after a recover, attempt item 1.
If a recover fails; open a new drawing and insert it into the new drawing.
You might also try the last item after any of the other items are complete, just to leave out any of the garbage that gets left behind, like defpoints and such. Only, don't insert, but copybase using a selection, not "ALL" and pasting it into the new drawing.
P.S. If none of the above works, you may have a useless drawing.