My iMac displays ye olde folder with a question mark upon power up. It was running in classic under 10.3.5 when members of my family (who shall remain nameless, but I'm married to one, and the other one is 3 years old

) did god knows what to it.
Am I correct in assuming that the start up volume is cooked in one way or another?
Why cannot I use my iBook via firewire, also running 10.3.5, as an external boot drive to get my iMac up and running?
Alternately, I have an external fw hd. How do I go about making this a bootable volume for this and future issues?
Or should i just use target mode to get all the important stuff of the iMac's hd and do a fresh install with the iMac system cd's followed by 10.3?
A bunch of questions, I know. I'm leaning towards the fresh install myself, but maybe there is an option I've missed. I'll admit that I'm somewhat of a noob with all this!
Thx