System hangs on inserting USB memory stick

[Vaughn Treude]

Hello everyone:
This weird thing suddenly started happening to me. I have a 256 MB
Memorex USB drive, which I can normally just insert into my system
(running Mandrake 10.)  The LED on the drive comes on, and it's
automounted at /mnt/removable.  But twice in the last two days, when
I've inserted the drive, it has locked up the system hard.  Can't
ctrl-alt-del, ctrl-alt-backslash, ctrl-alt-F2 or anything.  Caps locks
and num locks don't toggle.  I can't even change the selection on the
KVM switch (which I use to run four systems from a single monitor-
keyboard- trackball setup.)  The only solution was to cycle power (well,
I guess I didn't try the reset button, but that's also pretty drastic.) 
After reboot the drive mounted without trouble.  I always do a umount of
the drive before  physically removing it, so I don't think it's my
fault.  The only other problem I've noticed is that Mozilla has started
"pausing" for a second or two when I have several windows open.  I
checked for suspicious processes and haven't seen any yet.  I couldn't
find anything about this on the linux forum website.  Any thoughts on
what I should try next?
Thanks,
Vaughn

PS:  The syslog shows these messages just before the hang:
Feb 24 11:51:34 nakota harddrake2[14556]: ### Program is starting ###
Feb 24 11:51:40 nakota harddrake2[14635]: ### Program is starting ###
Feb 24 11:52:11 nakota harddrake2[14635]: modified file
/etc/sysconfig/harddrake2/ui.conf
Feb 24 12:01:00 nakota CROND[14839]: (root) CMD (nice -n 19 run-parts
/etc/cron.hourly)

I doubt these messages were related, though, because it actually hung
around 12:30 and I know I manually ran harddrake because I forgot what
SCSI card I had installed.