>We have an old software, still in Visual FoxPro version 3; on Windows XP, we get an error message, something like "Insufficient memory".
>
>Did anyone else have this problem with VFP 3 / Windows XP?
AFAIR there where 2 versions of vfp3 with different maximal memory problem border lines.
If you need to run on current hardware create a boot option line in boot.ini with the /MaxMem=510 (easily verified in the task manager). This should always work - you can try if you have the later vfp3 version by raising the memory limit up to 765.

HTH

thomas