osx forgot which partition to boot from

my friend just called me and his brand new 20" imac froze up last nite. he said he could only do a hard shut down. now when he powers up, instead of going straight to the logon screen, he's presented with an arrow and a (i believe) pic of an imac, or maybe a hd. he then hits 'enter' and everything's fine. i pretty much knew that 'repair permissions' wouldn't fix it, but i had him try anyway. now i'm at my g4 powerbook looking around disk utility trying to find a 'use this volume to boot' button or something like that. i want my friend to think i'm smart.

anyone know this one?

thx!

#417600

Option 1: Look for the Startup Disk preference pane.

Option 2: Hold Option on boot? If I remember right, that brings up a boot menu of sorts.

#417695

system prefs > startup disk

#417886

d'oh! got it, thx guys...

#417893