If its locked then I dont think that you would be able to format it.
If it wasnt your boot drive then I was going to sugges tthat you uninstalled it from teh device manager then shut down and physically disconnected it then rebooted without it.
Then if you added it again windows would detect it as new hardware and reinstall it.
That may have sorted it.
As it appears to be your boot drive then thats not an option.
I would definately try and get the information off it somehow, either by making it a slave in your pc, if you have a spare drive that you can install an OS on or taking it to a friends and slaving it on his pc or similar.
What make of hard drive is it, is it SATA or IDE, what size is it and is it almost full ?