Hey slud,
You've got me a little stumped on this one. Do they only stop working while LabVIEW is open, meaning do they resume working when you close LabVIEW? Also, is there anything abnormal about your LabVIEW installation or your PC setup, like running LabVIEW from a network location, or running on a certain operating system, etc?
Brian B
Account Manager
National Instruments