There are many instruments drivers available at the National instruments website. Just go to the link below and click on "Downloads". If the driver that you are looking for is not there, go to the link and click on "Other Driver Resources". It links you to other sites that have instrument drivers.
http://zone.ni.com/idnet/
If you find a driver that is made for an older version of LabVIEW, you may still be able to use it in LabVIEW 5.0. For LabVIEW 3.x and up, you would just need to mass compile the vi's that are a part of the driver.
Kim L.
Applications Engineer
National Instruments