Quick two-step guideIf you find Windows 7 taskbar a little too bright or just want to change its transparency or color then follow these 2 steps.
1a. Click Start menu then in the Search field enter "enable or disable transparent glass". A small windows with results will show on the right side. Click the item with title "enable or disable transparent glass".
1b. Click Start menu then Settings->Control Panel.
In the Control Panel find item named "enable or disable transparent glass" and click it.
1c. On the desktop invoke the menu and choose the option on the bottom named "Personalize". A window will show:
Now choose "Window color". It's in the middle, on the bottom
2. Play with options shown. Below you can see options I chose for my needs.
When you are done click "Save changes".