so you've gone into Manage (right click Computer then manage)?
Then to the Disk Management section?
On the unallocated disk right click it and click format, then make sure the whole disk size is selected (in the window that has just popped up, then format the disk, by following the rest of the steps, which are easy enough.
After this is done, it will have formatting next to the drive you just have formatted, wait for it to finish, then it will appear in my computer.
any probs just get back to me