How to reboot my PowerBook g4 laptop
I am getting a blue screen with a spinning circle. My PowerBook G4 laptop won't reboot. Help!
POWERBOOK G4, Mac OS X (10.4.11)
This says Yosemite, but it still applies to Tiger (I have a Pismo PB w/ Tiger) > OS X Yosemite: If you see a blue screen at startup
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If you see a blank blue screen or a blue screen with a colored pinwheel when you try to start your Mac, but starting up doesn’t progress, you may have a problem with damaged or incompatible startup items or software.
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About the screens you see when your Mac starts up - Apple Support