You would need to take ownership of C:\Windows\Resources\Themes\Aero\aero.msstyles and then edit the font colour using something like Resource Hacker.
Take a look at the link for details: http://www.sevenforums.com/customization/24620-change-taskbars-font-color.html
Unfortunately, Microsoft applications have become having annoying appearance, all fading, white, no contrast, and pain to the eyes. This not only exists with Windows 7 but also with Office 2013.
Windows XP has the best appearance and is the most user-friendly. The colors are beautiful, helpful, and everything is systematic. There are two solutions, either return to Windows XP, or in Windows 7, open the Control Panel, choose Personalization, and then from the list of themes choose Windows Classic. (This option gives a good contrast, although it’s not as beautiful as the layout of XP, and I chose it.)
Window Colour section of the
Personalize control panel then click on the
Advanced Appearance Settings link/button and you should see the old Windows XP style dialog which lets you customise the individual elements of the desktop.
Preposterous that Microsoft did not and still does not allow changing taskbar’s text color, after much searching I have found a sane solution.
Classic Shell has an option to tweak the color of text directly, in addition to having tons of other options to customize the Start Menu, for example turning ‘All Programs’ into expandable tree menu like in Windows XP, Windows 7 and 10 – donate to the author people :).