During Windows startup all the Fonts in the system are loaded and this slows down the boot time and takes memory.

To see the Fonts currently installed in the system go to Control Panel -> Fonts.

To remove a font drag the unwanted font from the Fonts-folder into another folder, so one can restore the font incase it is actually needed.

To install a new font manually so it is registered correctly open the Fonts-folder and in the File-menu select "Install new font..." and browse to the folder containing the new font.

More Info MS KB314960