Mepis 8.0 shuts down after about 2 hours of non use
 

I'm running Mepis 8.0 on a 64 bit machine with 2GB of RAM. I do not have power saving feature activated.

For reasons unclear to me,Mepis shuts down (goes into hibernation?) after a couple hours of non activity and has to be re-booted.

I suspect a setting problem on my part but haven't been able to solve this annoying problem.

Dick