You know that annoying problem where a disk has been formatted strangely and you can't get the disk manager to delete all the partitions so you can merege them.
This is how you fix it.
Check this disk number in disk manager first:
Then open CMD, type: diskpart . Now your in the right utility.
Now type: select disk <disk number>
Then Clean and your all done!
You can also do create partition primary from here or just use the GUI.