Ladybarlow,
I don't know if you solved your monitor problem but you might try changing the power options for "Sleep modes" for both your monitor and PC. I had a similar problem years ago (2008) with my LG monitor and posted it on this forum. Here's what I tried that worked, for several years until that monitor finally died in 2011, apparently from a bad capacitor, and I replaced it with a 32-inch TV:
After much searching for 3 days on several forums including this one, one post from someone with similar problem to mine (monitor not returning from black screen after "time-out") suggested changing "Power Option" settings for monitor and computer to the "NEVER" option, so there is no time-out.
I did this yesterday and so far that has worked (both monitor and PC are never "sleeping", and my screen saver (one of Vista's generic ones already loaded) comes on after the chosen minutes but neither PC nor monitor go to "sleep". SO FAR, SO GOOD!
If you want to try this, the path to that option (on my Vista Home Premium) is Start / Control Panel / Hardware and Sound / Power Options / Choose when to turn off the display /
Then change "Turn off the display" to "NEVER"
and "Put the computer to sleep" to "NEVER"
Then click on "Save Changes".
While this undoubtedly uses more power, it may save my sanity while I search for the "real" cause...
P.S. That action did save my sanity!
I never had that problem again, but now I'm searching for a new browser to use on my Vista Home Premium since all the ones I've used (Chrome, IE, and soon, Firefox) quit supporting Vista. Firefox is quitting support in September 2017 and already, I can't get Firefox to connect with most websites and even can't get it to work with Yahoo my Yahoo mail most of the time. (I'm having to use my laptop running Windows 7 for browsing and mail.) I will post my browser problem in a separate forum topic.