usb drives no longer read

[James]

Hi Guys

As of the last updates I ran over the weekend one of my ubuntu 10.04 
systems will not read any usb drives. This netbook on the other hand does 
and is also 10.04. I've googled and tried a number of things, eg. making 
sure floppy support is disabled in bios, listing the modules related to usb 
that were loaded (none showed), adding the following to /etc/modules 
(btusb, usbserial, usb_storage, and usbhid). Still no difference. They (usb 
drives) just don't show up at all

Any ideas?

James