I had been using a Dynafont "KYOKASHO-W4" font without any problems, but this morning Photoshop would not let me use this and kept switching either to the Dyanfont KYOKASO-W3 font, or another Japanese font (a gothic Japanese font). I just installed Acrobat Pro the day before. Post hoc ergo propter hoc? Clearly something was corrupted. I have re-installed the fonts, uninstalled and re-installed Photoshop CS6, and uninstalled Acrobat. I need this font for the book I am writing which is a pictorial guide to Kanji, and evrything I have done do date has been in the above-mentioned font. This particular is one that is recommended by the Japanese Ministry of Science, Education, etc.
It does sound like something new (Acrobat would be a possible candidate) has messed things up.
On a PC, I would see if you have a System Restore Point, from before that installation. First, create a new System Restore Point for today, then boot to Safe Mode, and choose System Restore, choosing one of those older System Restore Points. Test. At worst, you have lost a few minutes, as you did the System Restore Point for today.
On a Mac, I think the similar function is Time Machine (?), but do not have any idea how that works.
Good luck, and hope you get your font back.
Europe, Middle East and Africa