Hello,
Sorry to hear you are having issues.

For setting Windows 7 style Start menu background color. Try this. On Start Menu Tab->With Windows 7 Style selected->Click on "Configure menu" Button-> Click on "Customize menu visual appearance-> If you wish to choose your own color turn off "Use automatic color for the start menu" than click "Pick Color..." button. Color picker windows open. Choose your color and click "OK". Once that is done you should have change your background.

To change Taskbar background color. Choose Taskbar tab-> Click on "Taskbar blur transparency and color" button-> Turn "Use automatic color for the taskbar" Off-> Click "Pick Color..."-> Choose your color and click "OK".

Basj,
Stardock Community Assistant.