Try moving the disk to another sata controller. This MB has two sata 
controllers. 4 internal sata ports are on the intel southbridge, but one 
internal (and the pata and one external sata) are on a JMicron JMB363 
controller which is not supported in older kernels. My guess is you have 
the sata harddisk connected to the jmicro.

Roelof

Ken Teh wrote:
> I tried to install 5.1 x86_64 on a p5b-vm se.  Apparently, the 
> installation kernel does not see the SATA disk.  I booted the system 
> with Ubuntu's latest offering, 8.04, and looking at dmesg I see the 
> disk listed.  Its kernel is 2.6.24.  I'm guessing the 5.1 install 
> disk's kernel is an earlier version. What is its version and can 
> someone suggest how I might solve this problem?
>
> Thanks! Ken