A:
If there is anything on the drive move it to your desk top. Then... Go to your START menu (bottom left corner) > RIGHT click on Computer> this will pull up a box that says "Computer Management" at the top. Go to DISK MANAGEMENT, on the left, under the Storage tab, It will then pull up all drives connected to your computer. Choose your Thumb/Flash drive, RIGHT click on it (make sure to right click on the RIGHT side of the description.) Once you right click a menu will pop up, click FORMAT> then follow directions.
Summary: This will erase everything on the thubdrive and will allow full capacity to the drive, (which you probably had anyway) but at least you can try this out and see if it works.