AKIFIF: Macintosh OS 10.2 Startup CD?

My wife's computer (a desk-lamp iMac of approximately 2004 vintage, running 10.2.something) has been stuck on the blue screen for a couple of days now.

I suspect it's a problem with the user files, and I think I could fix it without too much trouble if I could boot the damn thing into a normal system from a CD, but the only thing I have are Restore CDs, Software Install CDs, and Upgrade CDs -- I don't have a single disc that's simply a bootable system; they all start some software process I don't want.

Does anyone out there know of a place to download old Mac system software, so I can burn a CD or DVD to run on her computer? I can't make one from the system on this computer, because this is an Intel Mac running 10.5.2, and that's too rich for the other Mac.

This is really annoying; I have this stack of CDs with something like an OS on them, and a long list of things to try to fix from Apple.com, but the first step is "start up from a CD." (Or in "safe mode," which isn't working.)

Update, Monday: Thanks, Brad! Target mode worked: I copied the hard drive on the dodgy iMac to a backup (once I'd lugged it over to where the other computer lived), and then a clean install fixed things.

I feel lucky that I've run Macs for nearly twenty years now, and I've never had to do a clean install before -- and I'll be even happier if it's twenty years until I have to do it again.

(The lurking issue now is that the OS install from the disc I had didn't include Classic...and I do find having Classic on at least one computer to be useful, so I'm trying to get that back.)