FC4 not recognising USB

[Dotan Cohen]

Until recently, I could put my disk-on-key into the computer and in
KDiskFree I could mount it. Now, I insert it, and nothing shows up in
KDiskFree. I also tried with a friends disk-on-key to verify that the
device itself is not at fault, with no luck. Also, the disk-on-key
works fine on other computers.

Where would I go to start troubleshooting this? Some simple googleing
led me to suspect a file called fstab, but I have no idea how to play
with that file.

Dotan Cohen
http://technology-sleuth.com/long_answer/what_is_a_cellphone.html