Windows 7 How to "sfc /scannow" an offline Win7 on hard disk from booted Win10?

Hi Peter,
I'm not familiar with the ToolsCD you mention. But, I don't think that modification to the sfc command is going to work, since you have no way of unmounting the volume and fixing it while running the volume mounted, which it needs to be while W7 is running.

The way I would approach fixing that would be to boot the USB drive that contains the W7 bootable image via download from the Microsoft MCT tool site (use their ISO file), and go into Advanced Recovery, where you can essential run several repairs including sfc (along with chkdsk and dism). This process essentially unmounts the W7 volume so it can be worked upon using Windows SAFE MODE Administrator level option to do so. You can also run Startup Repair, which rarely works from that menu. And then go through all 3 windows repairs tools in this order #1: chkdsk, #2: sfc, and finally #3: dism. You say your W7 is corrupted, but you don't say how it manifests itself. Do you get a BSOD, Black Screen, no display on boot? If it's not a BSOD, then these repairs can sometimes fix a bad W7 startup, by repairing the MBR, boot sector, boot track 0, etc. Hopefully, that will produce a fix for you!

If it doesn't, then there's a good likelihood that you have a more difficult problem and you could have several windows registry corruption, or a catastrophic hardware failure (Hard Drive, RAM stick(s), or Mobo). At this point it would be prudent to conduct Hardware testing on that computer, and if errors are returned on the hardware it has failed and must be replaced. If no errors are detected, you can then proceed to a W7 reset or W7 reinstallation from factory media/partition. All of this is described in my free TROUBLESHOOTING GUIDE available here: Windows 10 - Unclickable Task Bar

In my opinion, this is a better way to go, unless someone else here has had more luck with sfc command switches than I have.

Let us know how it comes out. We'd be interested in your final solution, or if you have questions while testing your hardware, post back here to this thread and we'll get back to you.

Best,
<<BBJ>>