Yes...better than a restore point.

In your case...if you have only 2 drives...do a full image of C and put it on the D.

As scorpNZ said...it's even better if you can have redundancy backups...that is...a third drive onto which also goes the backup of C.

Image restoring is by far the best protection method....particularly when a restore only takes minutes....where-as a new OS install combined with all the apps, etc can literally take weeks....;)

1-So long as the operating system & it's files are on C then D is irrelevant tho it would be good to create 1 file/partition image of D to save time; tho it won't need to be restored at the same time as C;only time you need to restore D is if something happens to D say a virus or corruption

2-You MUST get an external hard drive even if it's only 1; as you will NOT be able to restore from the same physical hard drive if both the OS (Operating System) & back up image are on the same single whole hdd regardless if partitioned or not

3-Forgot to mention last post,you can reduce overall image size if before hand you disable temporarily the pagefile (will require reboot) after which do a defrag then create a backup image; it will be necessary not to use any other programs while creating an image;would most probably pay to set the imaging program to low priority in case not enough ram is an issue,you maybe able to this from the task manger before executing a backup

4-ALWAYS create single system image files for C,or file/partition images if you want to backup C&D at the same time;as using differential & the other one i can't think of at the mo are extremely prone to corruption