During a client migration due to very old machines being replaced we encountered an issue where the client had a 16 bit foxpro dos application which needed to be maintained even though the client was migrating to Windows 7. The actual problem was that the new machines were to be Windows 7 64 bit.
Where attempting to create a shortcut or simply starting the 16 bit application that basically it was not a 64 bit application and would not run. A discussion with the software supplier found that they had only tested with Windows 7 32 bit and that the problem was truly the 64 bit nature of the OS.
In the end it was simpler to use the virtualisation layer called Xp Mode and create a vm for the user for the application – Changing the network for XP Mode to use the network card in the host and then joining the virtual machine to the domain to map drives and printers allowed the dos application to be configured as a simple use vm program.
Client happy and application working after a change to the config.nt file after a “too many open files” error – so xp mode says the day after Microsoft remove the 16 bit support.