Windows 7 has a taskbar that is dramatically redesigned compared to previous versions of Windows. Because the taskbar has a taller height than that of previous Windows versions, there is room for the clock to display more information. By default, the system clock displays the time and date. If you raise the taskbar an additional level, the day of the week appears. If you prefer a taskbar that only shows the time and date, you can lower the taskbar one level or change the date format used by Windows 7.
Right-click an open area of the taskbar, and remove the check from "Lock the Taskbar."
Hover the mouse cursor over the top part of the taskbar until the cursor changes to a double arrow.
Click and hold the mouse button, and drag the taskbar down until the day of the week disappears. Release the mouse button.
Right-click the taskbar, and select "Lock the Taskbar."
Right-click the taskbar clock, and select "Adjust date/time."
Click the "Change date and time" button. The "Date and Time Settings" window appears.
Click the blue "Change calendar settings" link at the bottom of the window. The "Customize Format" window appears. In this window, next to "Long Date," you should see the letters "dddd, MMMM dd, yyyy." The group of four lower case Ds symbolises the day of the week.
Remove the four lower case Ds along with the comma and space after them. The space after "Long Date" should now read "MMMM dd, yyyy."
Click "OK" in each open window. Windows 7 no longer displays the day of the week in the system tray.
You can also remove the day of the week from the system tray clock by lowering the taskbar in Windows XP and Windows Vista.