Suse 10 Shutdown Problem

After a while (dosen't matter how long, can be 10 min can be 30 min) I get a error that i can't read (because it apeares and dissapeares in like 1 micro sec). but afther some repeated attempts I made out something like "system halt...."
and it shuts down (no reset, no standby or enything just shut down!!!)
Any ideas???

You can probably read about it from logfiles in /var/log. Maybe /var/log/messages.