Why myserver be locked ?

[Halid Faith]

Hello

I have a Dell1600SC server. The server has 4 CPU and 2 Gbyte Ram. I had been using it based Redhat9 till a month ago.
The server was working without problem. After that,  I installed FreeBSD6 Release on it.

The server started to run be locked. When it is locked, it becomes as freeze.I am not able to do anything on it.
I don't believe in any hardware error. I have to push the reset button to reboot it. When I rebooted by the reset button, the machine has not given me any error message in dmesg and /var/log/messages. 
When the machine rebooted,  it works normaly with all of it's services.

What should I do ?

Thanks.