Check the screensaver settings. Is it set to return to login screen when coming out of screen saver?
Thank you, arael!
Your suggestion worked!
Yours is the best answer!
Thank you too nikorr for coming in. I used a factory DVD. I have set the screensaver to "None" and therefore no screen saver comes up. This annoying autolock used to come at random intervals. Anyway it is behind me now, thanks to areal.
I am now trying to decipher two other small windows - one coming at POST time - "Entering Power Save Mode" and another after Starting Windows - "1 Digital". I probably don't need to worry about them. Any thoughts? Shall revert to you again!