USB San Disk Cruser Micro & Mini flash drives won't work on my Del

This PC has four USB ports, two are legacy (V1.0 -1.1) and two are new Belkin USB 2.0 PCI ports and all of these ports will recognize those both Cruser flash drives as "new hardware". Have upgraded both flash drive drivers but no luck getting the flash drives to work.

Have tried to install updated drivers to allow either flash drive to function - with no luck. The same 4 USB ports will show the "plug and play" notes, and recognize a USB connected Epson scanner that works with no problem.

Under My Computer, Device Manager, Universal Bus Serial Controllers, USB Mass Storage Device does not show up as it does in my other XP Pro PC. The Dell Opitplex GX1p Device Manager does show other enteries, such as 4 versions of USB Root Hub, 2 versions of NEC PCI to USB Host Controller, one version of Standard Enhanced PCI to USB Host Controller.

This Dell PC was recently upgraded from WIN 98 SE to XP Home, with SP #1.

Appreciate any help or suggestions?