Hi,

You can use ‘D’ drive to save ‘My Documents’ folder and free up space on your ‘C’ drive. However, most installers by default get saved on ‘C’ drive. Using ‘D’ drive will not mess the computer.

Alternately, you can merge the ‘D’ drive with ‘C’ drive and have just one drive on your computer. Here are the steps:
Note: Please ensure that you back up the data before performing the steps below.

1. Click on ‘Start’
2. Right click on ‘Computer’
3. Click on ‘Manage’
4. In the Computer Management window, click ‘Disk Management’ in the left-hand pane
5. In the right-hand pane, right click the ‘D’ drive (not the C: partition)
6. Click ‘Delete Volume’
   
   
   
   
7. On the Delete Simple Volume window, click ‘Yes’
   
   
   
   
8. Now right click on ‘C’ drive, click ‘Extend Volume’
   
   
   
   
9. On the Extend Volume Wizard window, click ‘Next’
10. On the Select Disks window (do not change any value), click ‘Next’
11. Click on ‘Finish’
12. Close all windows and restart the computer

Please reply if you have any questions 

Hi, I tried your solution but found at step 6 that Delete Volume was disabled (greyed out).    Shrink volume was allowed.   Any further suggestions?

Hi,

Thank you for your response. Let’s try to format the drive and see if it works.
Note: Please ensure that you back up the data before performing the steps below.

1. Click on ‘Start’
2. Right click on ‘Computer’
3. Click on ‘Manage’
4. In the Computer Management window, click ‘Disk Management’ in the left-hand pane
5. In the right-hand pane, right click the ‘D’ drive (not the C: partition)
6. Select ‘Format’
7. From the File system: drop-down list, choose ‘NTFS’
8. From the Allocation unit size: drop-down list, select ‘Default’
9. Place a check in the ‘Perform a quick format check box’
10. Click ‘OK’
11. To begin the format, click ‘OK’

Now try to delete the volume and extend volume by performing the steps that were mentioned in my previous post.

If you are not able to format the drive, then you can use the drive as a backup drive and backup your information.

Hope this helps.

"LONTJC"

Apart from repartitioning your hard drive you might be interested in reading this article (thoroughly).It's more or less easy to follow and gives you some additional information.I just googled - there are tons of articles on the web,so I just picked one for you.

www.guardian.co.uk/.../c-drive-d-drive-partitioning

I just noted this thread, as it has been a long time, but through the method above it is not data protective way so it is better to choose  like AOMEI Partition Assistant or Gparted live CD, it could allow you extend the C partition without data loss.