MS Shell Dlg 2 is a "logical font" or a font mapping shortcut used by software developers. When a programmer builds a Windows application, they face a challenge. They do not know which fonts are installed on the user's computer or what language the user speaks.
If you are a developer and want to replace MS Shell Dlg 2 in your application, or if you cannot restore it, use these standard fonts that look nearly identical: Download Ms Shell Dlg 2 Font Free