usb drive wont mount

[Linda]

I have a usb flash drive that did not properly umount. The 
volume label is no longer in /media but Nautilus still lists 
it in places and shows the option to mount. However if you 
try to mount the drive you get unable to mount an operation 
is pending this persists even after a reboot. To make 
matters worse I did the updates today and with it tries to 
install the new kernal the generating grub configuration 
file step hangs after the Found memtest86+image line. 
Looking online I found this was caused for atleast one user 
by a stale NFS mount so am guessing this might be the cause 
of my update problem I'm now concerned that if I shutdown I 
will no longer be able to reboot the system. Any help would 
be greatly appreciated.
                        Linda