A: Yes, if you format the C: drive. Always back up the KOEI folder in Documents to an external drive or cloud service like Google Drive.
The game attempted to write data but was interrupted (power loss, Alt+F4). Fix: Delete the corrupted saveXX.dat and replace it with a backup. If system.dat is corrupted, you must restore the entire folder from backup.
Where do game save files get placed in the computer? : r/Steam