Mfaklis: but my system had no problem sleeping with an opened window (Outlook) prior to make the registry changes Tommy1997 suggested. And even now it has no problem sleeping with Outlook open when...

Tommy1977, I made the changes to the 3 sub-keys, changing the time to 20 minutes (1200 decimal) and now my system no longer goes to sleep after 2 minutes.
BUT, now it NEVER goes in to sleep mode...