The easiest way to find out what version of VISA you have is to open up MAX and look at the version number under the Software listing. You can also look at the VISA Interactive Control help menu About screen. If you want to be able to query this programmatically from LabVIEW, you can probably do it by querying the registry. The registry entry is under HKEY_LocalMachine\Software\National Instruments\NI-VISA. There is a "current version" listing that should give the infromation.
