As you've used a plug-in PCI card, I take it the motherboard must be fairly old not to have on-board USB ports.
Look on the disk that came with the card to see if there's any kind of installation programme to run.
You could try moving the card to a different PCI slot. Check the BIOS to see if IRQs are automatically allocated to specific PCI slots. If possible, allocate an IRQ not currently in use to the slot in which the USB card is placed.
And, as mentioned before, check Dynax website for any possible updated drivers.
ROGER - G0AOZ.