Quite possible Qemu may have worked, but the other two products are considerably more complex to use. The PITA factor would more than balance out the cost, being a customer application. Using the VPC is pretty much a no-brainer - it was dead easy to set up, and the 45day free trial made it risk free …

I solved the problem. I bought Microsoft Virtual PC 2004. Works like a charm!!

I will look at the code and try to post a snippet where it does the I/O

I have a basic program that is being run on a Win95 desktop as well as a couple ancient handhelds for data aquazition. The data is transfered by RS232 on Com 1: I need to run the program on a WinXP Pro box first, and eventually on WinXP laptops without com ports (use PCMCIA com port or USB/Comm: …