i hate external drives that require software to run. unless its only drivers you updated.
now if it were a desktop id suggest taking the HDD out and sticking it in your pc.. but thats an issue here.
If you have another computer to try it on then i suggest trying that. When ever ive had the old "write protected" issue its normally only been with flash drives and its because they are duff.
Also as an after thought, a system restore to a date when it worked may pay off, but its probably a long shot