Issues with external HD, changed to read-only

["Eric A. Bonney" <mailinglists@vanhlebarsoftware.com>]

I have an external hard drive that for some reason in the last couple of 
days was changed to a read-only file system.  I have looked at 
/etc/fstab and the drive is being mounted correctly as rw.  I have 
looked at the permissions of the drive and they all seem correct also.  
Even if I am logged in as su, I am not able to delete any files on the 
drive.

Is there a way to change this so that the drive works correctly?  All 
the other drives are working properly, just not this one.

Thanks,
-Eric