No problem with overwriting saves, either. I use different saves per mission for different phases of a patrol - first save is used for when I'm en route from the harbor to my first assignment, I have an "On The Hunt" save which is used when I'm patrolling an area in search of prey, a "Contact!" save when I spot said prey, a save for when the encounter is over and I'm distanced from the scene of the crime and don't have any contacts, and a last save for the trip home. I overwrite those saves every time the criterion for saving in the particular "slot" is met, and I'm ALWAYS surfaced. "Why so many saves?", might you ask. Simple: my old rig was prone to CTDs, and the power grid in Greece is not the most reliable in the world.

Soundman, do yourself and your PC a HUGE favor and ditch Vista!