Fix-it-up methods?

Since I had trouble burning a CD, which disappeared from the desktop and could only, eventually, be ejected by restarting with the mouse held down, I've been having problems with my new G4 PowerBook.

Sometimes the command keys don't work - for instance, cmd-Q doesn't quit programs.

Sometimes the keyboard won't type at all - for instance, I was trying to save a test Quark page in Classic, so I could then make a PDF test page, and the printer file just wouldn't let me type a name into it.

If this were my old G3 (now sold and *sob* gone from me), I'd run Disk Warrior followed by Norton, trash a few prefs, rebuild the desktop, and if the worst came to the worst reset the PRAM.

But is there anything I can do on an OS X machine that'll put manners on it?