Display dims slowly

My company just did a refresh of our desktops and has rolled out Dell OptiPlex 3040s running Win 7 Pro. We have found an annoying problem in the screes will begin to gradually dim down to the point that you can't see anything. This can happen when it is idle or in use and it isn't the monitor itself as changing the monitor while this is happening doesn't change anything as well as it happens with various models of monitors. I have looked in the power options as most help articles say to disable the auto dimming feature but I am not finding that option listed. The only way to get the display to return is to reboot the computer. As you can guess this is very inconvenient. Has anyone else seen this behavior before and figured out how to fix it?

It isn't a laptop and I don't have those options.

Nothing of those options are exclusive for notebooks, they're always available.
The screen is located in Control Panel => Energy Options => Change plan settings (for the enabled plan)

On desktops, the "On battery" settings are simply ignored, but the rest works.

My W7 desktop does not list screen dimming options.