Some distributions of Linux use a different default screen font, resulting in strange fonts when using MC in PuTTY.
The following fixes this problem.
Backup /etc/sysconfig/i18n – then clear the contents of the existing file and add the following lines:
LANG="en_GB.iso885915" SUPPORTED="en_GB.iso885915:en_GB:en:en_US.iso885915:en_US:en" SYSFONT="lat0-sun16" SYSFONTACM="iso15"
Log out and back in again, and MC will now display correctly.
Sorted.