Sorry, I meant its a powerbook g4. I stupidl , changed my startup disk to diskwarrior 4. I have tried booting holding down the c, x and option, command p+ o keys.
I just end up either with the finder folder icon or the padlock screen which requires a password, and my login password does not work
There's a bit of an old joke in Mac circles along the lines of "oh, try resetting your PRAM." On older models it apparently used to be a matter of course.
Certainly less so now.
But it still may help (especially given that it seems to store the startup disk location).
If you do get it back but Apple were right all along thinking your drive is toast, then the first thing to do is backup all your documents as fast as you can.