Monitor turns off by itself during normal usage.

There are a few things you can try in order to narrow the the cause. First there's the easy outside-the-PC stuff such as:

- hook up a different power cable
- hook up a different video (VGA/DVI) cable
- You can always try switching to the other type of cable (try VGA if you're on DVI and vice-versa) to see if that makes a difference, assuming your monitor as both connectors.
- try connecting same monitor (and power/video cable) to a different PC for a day and see if it turns off there as well.
- For that matter connecting a "known good" monitor to your PC to see if that monitor also acts that way on your PC.

On the software side you can disable the power management features related to the display to see if that makes any difference.

If you were to connect this to a different PC with a different VGA/DVI cable and power cable and it still did it that I would say it's probably the monitor itself (unless the PCs were identical or something and under control of the same domain policies or some craziness like that).

At some point you probably want to call the manufacturer and see if an RMA is an option. I would recommend trying some things before that though. I hope this helped!