The play.exe is a file used by Real Jukebox.  If you recently uninstalled
Real Jukebox, you'll get the message that play.exe can't be found.  Real
Jukebox changes the file association, and after you uninstall it, you need
to change the file association back to what it was before you installed the
Real Jukebox program.

Go into Windows Explorer.  Use Alt with V to bring up the view menu.  Arrow
up to folder options.   Pressing enter on Folder Options will bring up a
dialog box.  Use shift tab to get to the tabs or headings in the dialog box.
You'll probably land on General Tab.  Right arrow to the File Type tab.
Then use your tab key to go to the list view of programs.  Arrow down to
AudioCD.  Tab to the Edit button and hit enter.  You should land on a field
called description of type, which will probably have CDAudio already in the
field.  Tab once and make sure play is selected.  Then tab to the edit
button and press it.  In the Application used to perform action, you should
take out the play.exe, and change it to be c:\windows\cdplayer.exe /play
Then tab to the OK button and press enter.  Then tab to close and press
enter.  Now you can use the Alt key with the function key 4 to leave the
program.  Before leaving, you might check the list to see if besides the CD
Audio choice, you might also have CDAudio tracks in the list.  If so, follow
the same procedure a shown for the CD Audio choice.