Summary
The only monospaced TrueType fonts shipped by Microsoft are Courier New, which shipped with Windows 3.1, and Lucida Sans Typewriter, which was included in the TrueType Font Pack. All other TrueType fonts included with Windows 3.1 and the TrueType Font Pack are proportional fonts.
More Information
Monospaced and proportional refer to the distance between each character in a font. Monospaced fonts have constant spacing between characters while proportional fonts have variable spacing between characters.