Try using a partition manager such as Gparted. I use Puppy, which includes it.
You can delete the partition and then set and format another; if it's locked and won't let you, you can also change the flags. You don't have to use a linux format, there is a choice of quite a lot of file systems.
The only catch wit this is you will lose any data on the drive.
(If you can) backup the files you want to keep then just format it, Fat32 is the file system you will most likely want to use.
All you really need is a disk partitioner that goes around microsoft locks, linux is great for it as it's free and linux will generally let you do anything destructive or not as long as you tell it to (su sudo). Note linux is case sensitive.