You will need
  • Partition Manager.
To start, try to use standard programs of Windows operating system. Open control panel and navigate to "System and security". Select the submenu "Administration" and open it.
Open the Manage diskmi. Select one of the partitions on your hard diskthat will participate in the connection process. Click right mouse button and select "Delete volume".
Repeat the above operation for the second partition. Now click "Create volume". Specify the file system format and size of the future section. Note that this operation can't be done with the system partition. All the files on both diskx will be removed.
If you need to make this operation without losing data or in the process of merging will participate to the system disk, use the special utility. Download program Paragon Partition Manager.
Install this app on your computer and restart the operating system. Run The Partition Manager. Activate the Mode "power user".
Click the "Wizard" located on the toolbar of the program. Go to menu "Additional functions" and click on "merge partition".
Click "Next" to go to the settings sections. Select two disk, in this case it will be drive C and D. Click "Next".
A window will appear with a warning that you combine a non-system partition with the system. Click "Yes" to continue. A window will open showing the status of the partitions on your hard disk before and after the merger. Click "Next".
Click "Finish" to apply the settings. To start the process of merging the partitions, click "Apply pending changes".