problems running freebsd 6.0+

[Tom Cruickshank]

Hello,
     I'm hoping is the correct mailing list for this, if not, please feel
free to direct me to a more appriopriate one.
I have a box which I'm trying to run FreeBSD on. I can run FreeBSD 5.4 on it
without any problems, but if I try run
FreeBSD 6.0 or 6.1, at any point in time while the system is running (could
be on load up or when system is already loaded),
the computer just *freezes*.  The only thing which can be done afterwards is
a cold reboot. I hav checked the /var/log/messages
file and haven't been able to find anything wrong.

Hardware specs:

Motherboard: A7N8X-X

Has anyone ever had this kind of problem themselves or heard of it?

Any help would be appreicated. Thanks!

Tom Cruickshank