Partitions must be consecutive. So you need to move D to the end of the disk first. That can't be done by Windows Disk Management, alas. There are free partition managers like GPARTED or the home edition from Aomei, and I see no reason to not use it. But just for safety, make a backup of all contents to another device first.
Kees
Hi, my question could be an old one but I cannot find the answers so I am requesting for your helps.
My notebook computer (OS Windows 7) has SSD drive I did partition C: and D: long time ago. Now the drive C: is got red means free space is so little and drive D: is still has a lot of free space.
To add some free space from drive D: to C: I used disk management and shrunk the drive D: and got another partition drive F: with free space 10 GB it is located to the right sight of the D: in Disk management window. I can re-merge this 10GB to D: but cannot merge to drive C: . There is one possibility I found on Google is back up the drive D: and delete the volume and re-partition or use a software such as Partition Magic. So my question is how can I merge this 10 GB( disk space from drive D
to C without using a third party software and without deleting drive D:?
Regards,
Wildbird

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic