Monitor keeps going into sleep mode
My Dell XP8300 with i7 processor and 8GB RAM with a AMD 6670 1GB graphics and DEll ST2320 LCD monitor is starting to act odd! A week ago I was finding that if I plugged any USB device in or plugged my SD card into the built in reader the monitor went black/sleep mode. If I waggled the mouse the screen woke up. But if I unplugged the device or removed the card the monitor shut down again! Rebooting the computer cured this issue. But tonight it started doing it again when I tried to play a CD. As the windows player appeared on the screen the monitor again went black. And after waking it up, found the previous sources (USB/card reader) would be it into sleep mode again. Another reboot and everything is fine- for now?
Apart from some windows updates about 11 days ago nothing has been added or removed or changed to my system. Any ideas?
I do have the monitor set to go into sleep mode after 30 minutes which has been working correctly. But even disabling this made no difference!