The D: drive is a partition on your main drive that contains an image of the factory installed operating system to be used to completely reinstall the OS. IT IS NOT TO BE USED TO STORE ANYTHING. You need a second drive either internal or external.
If you havr no Restore Points, you need to go to the Restore page in the Control Panel and turn Restore on.
I have a Dell Desktop Inspiron 530 with Vista. I keep getting a message that my D drive is full and to click the icon to clean the drive. The pop up says, " You can use Disk Cleanup to free up 0 bytes of disk space on Recovery D." So that's useless. I also can't use the restore function on my computer because the computer tells me I have no restore points. I need suggestions to free up space on recovery drive D. I have tons of ram and my other drive is 90% free.