Resolved Acer S201HL - Can't adjust Brightness - eDisplay Management greyed out

Hi,
My first post.
I can't adjust monitor brightness.
I just received an Acer S201HL monitor and installed it yesterday. The screen is too bright, and I tried to access the control. The Adjust and Color radio buttons are greyed out in "Acer eDisplay Management ". So, I tried using the controls at the bottom-right of the monitor. I get as far as displaying the brightness and contrast window. But, I can't make any adjustments on that panel. Brightness is displayed as 100%. I did a web search, and I found that many Acer monitor users have the same problem. It appears to me that the up/down and left/right keyboard arrows should be able to modify the display, as they are indicated at the bottom of that panel. The keyboard arrows don't move anything. I tried with my mouse, as well. Nothing. Instructions are sparse. By reputation: Acer has terrible customer service. I'd appreciate help in getting this problem solved.

W7 (64), SP1. 2.9 GHz AMD Athlon II x 4, 10 GB Installed Memory
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I discovered the cause of the problem. The file that came on the installation disk is corrupt. I wiped it from my computer. Then, I downloaded a copy from Acer's website. It has the same file date and size as the one on the CD. But, when I installed it, it worked as it should. I was able to make adjustments to the monitor, as none of the Radio buttons were greyed out. I hope this resolution will be helpful to anyone searching for an answer to a similar problem.