Studio XPS card reader (Desktop)

I bought my Studio XPS in July with Vista 64 bit.  The card reader worke fine.  I upgraded to Windows 7 and now when I put in a card nothing happens.  Devices show an "unknown device".  The USB port on the right side of the reader works.  The card reader is on the top of the tower.  Tech support installed every driver they could find for it but to no avail.  A technician arrived today and installed a new reader with exactly the same problem.  My slight computer knowledge says I either need to know the exact driver to use, or there is a problem with compatibility with Windows 7 and I need to know when that will be solved.  Our best guess on the manufacturer is Dell, only because the Dell name is stamped into the part and there is a Dell part number and not other markings we can find.  Help would be appreciated.