To determine your OS version, tab Start menu then choose Settings command. Tap system tab, below the screen, then tap over the about icon. You will get all information about for iPaq.
Typically, most of previous version are able to run under your iPaq but the application menu bar will appears on top of screen rather than the bottom. So, will will get a little problem about Shell Input Panel (SIP).
For your last question, if the software you are looking for use advance advantage of the color screen by using direct hardware access, such as using GAPI. The program could not be run under your iPAQ. But if the program were writtern to support all devices, multi-platform support, you may run the program. So, trial version could help you at this point.