mount: could not find filesystem '/dev/root'

[Jim Bevier]

Then
Kernel panic - not syncing: Attempted to kill init!

This was an ASUS k8v se delux with AMD 3400 processor.  It was running FC6 
and rawhide (up to date as of 4/3).  I replaced the motherboad with an ASUS 
MSN-plus SLI with an AMD X2 4600.  I can boot FC6 with not problems and see 
the two pata drives on the system.  There are no SATA drives and the 
controller is disabled in the bios.  I can also boot the FC7t3 live dvd and 
it work great, but the old rawhide will not boot.  What can I do to get it 
to boot again?  Why will it not find the root filesystem?

I need some help, please.

Jim