For the archives:
I had an odd installation hang on an older Athlon MB; KT133 I believe.
SuSE 10.0 and Fedora Core 5 installers ran fine; CentOS 4.2 and 4.3 hung with the last line on the screen referencing running /sbin/loader (or is that /sbin/installer....don't typically see it enough to remember); the cursor froze at that point. SuSE 10.0 successfully installed on this box.
After trying all the normal tricks, like turning ACPI off, using the BIOS IRQ table, etc, I noticed that the FC5 installer mentioned something about disabling IRQ6. IRQ6?!? That's the floppy controller; but there's no floppy drive configured or cabled. Hmmm.... no place in the BIOS to disable the floppy controller ?!? Ok, let's tell it it has a 3.5 1.44MB floppy (even though it doesn't!), and not to stop on floppy errors.
Lo and behold, that fixed the hang. Something in the CentOS 4 installer that runs right after /sbin/loader was hanging, unless it had a floppy out there, even when there was no floppy out there.
But, and I repeat, SuSE 10.0 installed flawlessly, and the FC5 installer came up fine. But the CentOS 4 installer did not until I told the BIOS to lie about having a floppy.