>Hi.
>
>I'm upgrading for a client to VFP but developer of existing Dos system is long gone. All i'm left with is the files and no documentation, and I need to take across the files.
>
>All data files seem to end with .DAT and index files with .IDX.
>

Unfortunately, neither was 'owned' by a particular program; FoxPro (and lots of other things) used .IDX files, and lots of stuff used the .DAT extension. You might want tolook at product's like Data Junction, a commercial data conversion tool which knows about lots of file types, or you might try surfing through the DOS executable with a hex editor looking for the name of the product...