How to shrink a partition?
Click with your right mouse button on 'Computer' and then click 'manage'.
The next screen is shown.
In this screen you click in the left pane on 'Disk Management' below 'Storage'.
Then the next screen is shown.
Now you see all your partitions which you have created. To shrink a partition you simple right click on the partition and in the menu which appears you click 'Shrink Volume'.
The next screen is then shown.
Here you can enter the amount of space to shrink in MB.
There one thing you can not do. You can not move a partition or extend it with an empty space which is in front of a partition.