If the saved state of simplify (found in C:\Users\your username here\AppData\Local\Simplify3D\S3D-Software-V5) is corrupted, which it has a coin's flip chance of being after a crash, simplify will instantly crash on startup. The only solution to fix this is to navigate to the file and delete it. A simple integrity check of the saved state file before simplify attempts to open it would fix this.
Hmm... I've never seen this happen on my computer. Can you attach one of the "corrupted" files that wouldn't open? Are you sure it isn't some kind of permissions issue instead?