Another possibility, pretty rare as we've only heard of this one once.
On Windows 7 or 8, likely a laptop, maybe NVideo video card, only certain larger monitors...
Check: The Registry setting KEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts\MS Sans Serif 8,10,12,14,18,24 if set to SSERIFF.FON was on a system which started at 125% DPI. The setting is supposed to be set to SSERIFE.FON on a system which started at 100% DPI. Notice that one character of the file name changes from F to E. E is the correct character.
The solution is simple: Change SSERIFF.FON to be SSERIFE.FON, the FF to FE. See Windows registry, 3 easy edits to complete the fix.
"MS Sans Serif 8,10,12,14,18,24"="SSERIFE.FON"
"MS Serif 8,10,12,14,18,24"="SERIFE.FON"
Source, Microsoft Dynamics Support Team, webpage: