Got Cent OS server 5.8 final installed on a Dell OptiPlex 380.
LSB Version: :core-4.0-amd64:core-4.0-ia32:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-ia32:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-ia32:printing-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 5.8 (Final)
This server restarts automatically at no specific time. Its a random event that happens everyday. May be couple of times a day.
I have looked at messages. I am attaching the messages file for reference. If anyone can let me know if you see anything weird. This has been going for long. Have contacted Dell Support for this. Have updated the BIOS version and RAM. But no go.
At about line no 35
you can see the restart message.