virtualbox.org

This is on PCLOS (fully updated) after upgrade. I had one WinXP image in a snapshot. The VM refused to start, complaining that the saved image was corrupt. I went to the Snapshots tab and right clicked on the Current State, only to find that I was unable to discard the snapshot (greyed out). So, I went to the .virtualbox directory, found the snapshot, and moved it to Trash. Now it won't start either. So I attempted to restore from Trash, only to find it wasn't there (separate problem).
So, how do I recover the original machine without rebuilding it from .iso?