Right-click any empty spot on the desktop and choose Properties from the shortcut menu.
Then Click the Appearance tab.
There, select the "Advanced" button:

Then, in the Advanced window, click on the "X" button in the image, and change the font size (it should be 22 or 23 if I remember correct).

Now press OK and then OK again, and your problem should be fixed.
(If it doesn't work the first time, try again with other font sizes...)
By the way, don't write the full message in capital letters..