F8 either rebooting or restarting X while I'm away

[G.Wolfe Woodbury]

On Fri, Dec 07, 2007 at 12:11:45PM -0600, Gerry Tool wrote:
> The past two days, when I return to my computer after being away -
> probably >= 1/2 hr, I find the login screen greeting me.  Since I
> don't see it happen, I don;t know if the computer is rebooting or if X
> is restarting.
> 
> Does anyone else experience this?
> 
> What should I look for in what log file to get a clue?
> 
> Thanks.
> 
> Gerry

Are you seeing the effect of 

  System -> Preferences -> Look&Feel -> Screensaver

having the "Lock screen when screensaver is active" box checked?

This causes a login-like dialogue to appear when you come back
from the screensaver.

-- 
Wolfe