Illustrator CS.
Not sure if there's a connection, but after installing some plugins
Illustrator icons are missing, and have been replaced with 'generic' windows
OS icons.
This is true for AI files and EPS files.
And when I try to open a couple of AI files by double clicking on them
without the Illustrator CS not open, the OS reports that they are not Valid
win32 files. If Illustrator is open already, these files open fine by
clicking on them in Explorer or on the desktop.