Due to the fact there were a lot of generic PCMCIA (PC CARD) to USB 2.0 devices on the market drivers can be a little hard to find. At the bottom of the page are a range of drivers you can try to install the adapter on an older operating system.
TechGear NEC PCI to USB Enhanced Host Controller B1 Driver
File: TechGear.zip
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SoftGate PCMCIA/USB Driver "Look in the AutoPlay\Docs folder for the executable for your device."
File: quetec.zip
5b4e31bc4b48ac566161e12a12a3f9ed55262b0b2d3eef50297b0e3b6ad77661
ST Lab PCMCIA/Cardbus USB 2.0 2port Adapter ST-Lab C111
File: USB 2.0.zip
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Digitus DC USB2PCMCIA USB 2.0 PCMCIA ADAPTER, 32 BIT-CARDBUS driver file
File: dcusb2pcmcia.zip
33aff1dcabbffd7be3cf51a6e23bab033edbd921f1fef658f9e07f3ee4927311
Chronos USB2.0 CardBus
File: usb2.0cardbus.zip
5ecc8e0064b20bd8cf7c220867fdb257f741e7ff268ca995eb7a4e63fe798a98
Kanguru Solutions Cardbus USB Adapter
File: CB_USB_Hub.zip
0858b3ab7ae28e1c535a22e168ba091558953ae94b2e12c2e74c195565d562c8
UTE200 USB 2.0 ExpressCard
File: ute200_2.01.0011.0.zip
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4 Port USB 2.0 Cardbus Card
USB Provided by the high performance chips
USB 2.0 Compliance
Data transfer rate up to 480 Mbps
Plug & Play
Fully compliant with USB 2.0 EHCI standards
Fully compliant with USB 1.1/1.0 OHCI standards Backwards compatible with old USB standard (1.1)
Supports 32 bit CardBus PC Card Type II slots
Supports Bus Power, 5V, 500mA per port
500mA current protection for device
Auto sense the connection speed
Requiremet
Available 32-bit CardBus / PCMCIA Type II slot
Microsoft Windows 98SE/ME/2000/XP