External HDD not working with USB 2 pcmcia card

[#1]

Hi all.
I have a relatively old laptop with only a couple of USB 1 ports. I've bought a pcmcia card to add USB 2 ports.
This recognises other USB 2 enabled devices with no problems.
I have an external HDD: when I connect it to the usb 1 port, it is recognised and installed as a HDD with no problems, but XP's taskbar it says it will work faster when connected to a USB 2 port.
when connected to the USB 2 port (on the USB powered pcmcia card) it's recognised as a USB human interface device and can't be used as a HDD.
The hdd can be connected to any other computer I've tried with USB 2 ports and is recognised correctly and installed with no problems.
Any ideas of where to start?
Cheers, and many thanks,
Tim

[#2]

Have a look at this:
http://ntcompatible.com/Desperately_need_help_---_USB_Devices_Not_Recognized_t32356.html
They suggest turning the machine off for 30 minutes, unplugging from the mains and trying again. It sounds a little wierd to me, but you never know....
Regards,
Neil