Hello Michael,
This is Dominic L. from Applications Engineering at National Instruments. You may use the LabVIEW Real-Time Module (RTX) for Windows to add a real-time component to a Windows 2000/XP desktop PC. In other words, this real-time OS would run in parallel with Windows on the same processor. This would allow you to run both the user interface and real-time application on a single PC. You can develop LabVIEW Real-Time applications using the Windows environment and then execute your code in the real-time extension environment.
As dwisti mentioned National Instruments LabVIEW Real-Time Module comes with two CDs: LabVIEW Real-Time Module (RTX) for Windows and Ardence RTX Run-Time. Thus, you do not need to purchase Venturecom RTX in order to run LabVIEW RTX.
Is there a reason why you prefer RTX over ETS?
I hope this helps.
Thanks so much and have a nice day!
Best Regards,
Dominic L.