unable to adjust brightness in my monitor

[CTS]

I've got a 20" Lenovo monitor hooked up to my Dell laptop with a VGA cable. I'd previously been using it as a second monitor on an iMac, via DVI.

I'm unable to adjust the brightness, however (I was able to before, both using the Mac's options and the buttons on the monitor).

On the monitor, the option to increase brightness comes up (using the buttons), but moving the slider makes no difference. I don't know Windows 7 well enough to know if there's a computer-based way to change the brightness. What to do?

[outouser]

Hi try to disable adaptive brigness. After that yoshould me able to manually adjust.

To turn adaptive brightness on or off

1. Open Power Options by clicking the Start button , clicking Control Panel, clicking System and Security, and then clicking Power Options.

2. Under any plan, click Change plan settings.

3. Click Change advanced power settings.

4. In the list, expand Display, and then expand Enable adaptive brightness.

5. To turn adaptive brightness on or off when your computer is running on battery power, click On battery, and then, in the list, click On or Off.

6. To turn adaptive brightness on or off when your computer is plugged into an outlet, click Plugged in, and then, in the list, click On or Off.

7. Click Apply. Click OK.

[magscoug]

Idea Pad U400 - brightness is turned up all the way and I still can't see; doesn't make a difference when i plug in so seems like brightness feature doesn't work. any help ?