when starting my 2009 mac book pro, it often shuts down before i can put my password in
when starting my 2009 macbook pro, it often shuts down before i can put my password in
See if you can run the Apple Hardware Test which can be found on the 2nd DVD which shipped with your Mac.
See if you can boot into Safe Mode.
See if you can boot into Recovery Mode using Command + R so you can run Disk Utility First Aid.
I suspect you most likely have a failing hard drive especially if you are still using the original drive.