If a keylogger gets on your computer can it see past passwords put on it or just ones entered after?

-if a keylogger gets on your computer can it see past passwords put on the computer or just ones entered after the keylogger got on the computer?A simple keylogger program intercepts your keystrokes as you type them into your computer, so it will only be able to see and record what you directly type after the keylogger was installed. However, if your computer is infected, be wary for other more complex spyware or viruses at play, too.
Just the ones after you enter
after