I followed some advice on the wiki System file check (SFC) Scan and Repair System Files to find out how to fix corrupted files that SFC couldn't (as I had previously already known about SFC) and came across this barrier.
Here is a log file of DISM, if you need. It includes information only from the execution of DISM described in this thread.
Also, in case you need it, is my Command Prompt. Instead of creating a screenshot, I just pasted it in plain text.
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Windows\system32>DISM /Online /Cleanup-Image /RestoreHealth
Deployment Image Servicing and Management tool
Image Version: 6.1.7600.16385
The restorehealth option is not recognized in this context.
For more information, refer to the help.
The DISM log file can be found at C:\Windows\Logs\DISM\dism.log