CompactFlash Adapter NOT Assigned Drive

I have a Viking 64MB compact flash card and a Memorex PC Card Adapter. When inserted into the PCMCIA dirve of a Dell laptop running Windows 95, the card is found and assigned a drive letter. I can then access the data. When insterted into the PCMCIA dirve of an HP Vestra running Windows NT, it knows the card is there (Control Panel/PCMCIA), but it is not assigned a drive letter and is not accessible under Disk Administrator. It is shown as “off line” under Disk Administrator. Can you suggest how to get it working short of buying a commercial product. Viking Support recommends CardWizard by SystemSoft.