A strange thing in Windows 7

Hi,

I just had a strange experience in Windows 7 32-bit on an old laptop.

I opened a command prompt as administrator and did

sfc /scannow

No problem there.

But after that I entered

Dism /Online /Cleanup-Image /ScanHealth

And in a few seconds the Command prompt replies with

The scanhealth option is not recognised in this context

That is something I have NEVER come across before.

Has anyone ever experienced or seen this before or can anyone explain this to me?

Thanks in advance.