2. Right click "Computer" select properties
3. Left column click on "System Protection"
4. Under the list of drives/partitions look for the one with "(missing)" as the description
5. Click on the "OS (C:)(missing)"
6. Click on Configure
7. Select "turn off system protection"
8. Click OK
9. The partition with "(missing)" should disappear
10. Now you should be able to turn on system restore for the real partitions
Click here to go to how to turn on system restore:
Source: http://answers.microsoft.com/en-us/windows/forum/windows_7-system/trying-to-expand-space-for-automatic-system/fab7cf13-26cf-42ab-bbf3-3bdd0c4489fb