Have you done any software updating or let anything update anything on your PC.  SOmetimes there have been problems with missing .dll files, but usually this has been with visualC+ DLLs  which are missing in a 64 bit windows install.

 

THere are redistributals availalbe at MS to sort this out.

The greatest part of wisdom is learning to develop  the ineffable genius of extracting the "neither here nor there" out of any situation...."