Hi NatzW,
What order are you installing the hardware and software in. Generally at National Instruments we recommend that you install the drivers first and then application software (although quite often during application software installation if will ask to update your driver software), and then install the hardware.
If you are installing hardware before you install software then it will cause problems. If you are getting problems with recognising the VISA functions from other programs, and reinstalling hasn't helped, then it is possible that you have a corrupt disk or something. Please go to the following link to download NI-VISA 3.2 and try installing it from here.
http://digital.ni.com/softlib.nsf/websearch/F20288844692F8D086256EE6006983D8?open
document&node=132060_US
Hope this helps,
Peter H
Applications Engineer
National Instruments