Another Fedora 18 Alpha story

[Bruno Wolff III]

On Mon, Sep 17, 2012 at 11:38:33 -0400,
   Timothy Davis <cpuobsessed at gmail.com> wrote:
>My system is an older Athlon FX-60 on a socket 939 nforce4 motherboard
>with two SATA drives and one IDE hard drive
>I wanted to install F18 on the IDE drive (140Gb WD) and went through
>the steps and selected a number of packages to install
>It appeared to installed just fine but when I went to boot into F18 it
>didn't exist! I booted into my F17 install and checked the disk
>with palimpset and it didn't find any partitions. I selected the
>automatic partitioning and made sure that there were no partitions on
>the disk when I started.

Is the IDE drive your boot device?

My first guess would be that it's booting off one of the sata drives, whose 
bootloader doesn't know about f18 on the IDE drive.