This is a Windows system installed file with Windows File Protection (WFP) enabled.
fontext.dll has 51 known versions, the most recent one is 6.1.7600.16385 (win7_rtm.090713-1255). The average file size is about 388.11 KB. Some variations of the file have been seen to be installed with the program NVIDIA Drivers from NVIDIA Corporation.
The Windows Font Folder shell extension contains all the font files used on the Windows system and implements the Windows fonts folder whenever new fonts are installed using the control panel or when new devices are installed. Windows Font Folder (fontext.dll) updates the list of fonts installed in Windows.
(Note, the behaviors below are for all versions of fontext.dll, select a unique version for details.)
Located in the registry at 'SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved'
United States installs about 48.13% of Windows Font Folder.