I had this problem before. It was a windows update that messed up my trebuchet fonts. Reinstalling it cured my last set of errors.

 

Now I have the same problem, and reinstalling trebuchet doesn't help. I don't know which other fonts to check... Can you help?

 

 

Did you tried to repair / reinstall NGX?

no

Then try  :lol:

 

tips:

 - From NGX airplane folders, backup your textures and airplane.cfg, so you don't need to re-install all textures after reinstall. You will need to manually coppy all textures and paste all cfg entries, but it's still much faster then installing again.

 - from Microsoft Flight Simulator X\PMDG backup NAVDATA folder

 - from Microsoft Flight Simulator X\PMDG\PMDG 737 NGX backup you ini files, to keep all your current settings / options. 

You can also try to fix whole problem, some metods: 

 

http://windows.microsoft.com/en-us/windows7/change-windows-fonts

 

http://www.sevenforums.com/tutorials/1175-fonts-change.html

Thanks guys! Those sets of advice could be useful!