Hayyyy guys, I'm having a major issue with my mom's G4 Mac Mini. Whenever I try booting it up, it goes to a grey screen; After a while, it shows a mac folder and a flashing question mark. I've tried power cycling it last time it happened and it worked; I tried the power cycle a few times today and nothing. When I power on, I do hear the powerup noise and the CD drive spinning up. It's a G4 Mac Mini, 512 ram...any help??