Question IMac 20' Self shut down and auto restart

[musicman48]

My iMac a 20"core Duo running 10.5.8 sometimes does a shutdown and restart right in the middle of work. Sometimes it freezes partway through start-up too.

 

[daship]

Go to apples website and ask.

 

[Baldand 50+]

My 27" iMac runs great with Win 7-32 bit, but if I leave it alone for a while, it will restart for no reason. About 20 minutes or so later, it will restart again, and will continue to restart every 20 minutes or so for as long as I leave the machine untouched.

As long as I'm working with it on the Windows partition, I have no problems. Also, it will sit without unplanned event for as long as I leave it if I'm running on the OSX partition.

I have changed settings for screen saver, go to sleep, and energy saver modes to "never."

It's just a nuisance as long as I remember to save my work and shut down all apps before I walk away from the machine. But I sure would like to be able to come back and find it just the way I left it.

I'm funny that way.