Neil,

MessageBox returns an integer value indicating one of the following:-

1 OK 
2 Cancel 
3 Abort 
4 Retry 
5 Ignore 
6 Yes 
7 No 

Also, these are defined in standard.h as preprocessor constants that are a little more self-documenting.

*!* MsgBox return values.
#DEFINE IDOK            1       && OK button pressed
#DEFINE IDCANCEL        2       && Cancel button pressed
#DEFINE IDABORT         3       && Abort button pressed
#DEFINE IDRETRY         4       && Retry button pressed
#DEFINE IDIGNORE        5       && Ignore button pressed
#DEFINE IDYES           6       && Yes button pressed
#DEFINE IDNO            7       && No button pressed

Regards
Neil