|The Turbo C/C++ you are trying to install/run is a DOS version so managed by the built-in emulator NTVDM (NT Virtual DOS Machine) as in XP there is no DOS at all being a NT kernel system.|
Usually NTVDM can allow running legacy DOS applications in a XP window, but sometime there are incompatibilties.
A workaround may be to download and set up a virtual machine then install and run the legacy application inside that environment.
Free virtual machines suggested are
- Microsoft Virtual PC
- Open Source VirtualBox
You need a legal copy of DOS too, but a free bootable diskette sufficies for the core of operating system. If you want a full DOS guest environment install FreeDOS, the free Open Source DOS clone.
If you choose MS Virtual PC and you are running Windows XP Home, ignore the warning message requiring the Pro edition: that refers to suppoprt policy only.