I don't know why you have mentioned Vista but in Win 10, go Start - type defrag and press enter when it comes up.
If that doesn't work then open either a Command Prompt (Admin) or Powershell (Admin) and enter these cmds -
dism /online /cleanup-image /restorehealth
sfc /scannow
Enter exit to close the cmd window and try again.
Let me know what the sfc /scannow reports.
