Hello!
Thank you for posting to the NI Forums! Because your other cards are working, it does stand to reason that there could be a problem with this particular card.
A couple of questions though:
1. Is the card recognized in your system's Device Manager under Data Acquisition devices? Is there any symbol other than the NI logo next to the card such as a yellow exclamation point?
2. Have you installed anything new to your system lately that could have affected the driver? This is not likely as your other cards are working.
If your card is not recognized in Device Manager and your DAQmx driver is up to date, then I would recommend calling into NI and asking about returning the device for repair/replacement depending on what your warranty allows.
Hope this helps!
Have a great day!