I recently replaced a HDD in one of my Toshiba laptops and got one from ebay but that was from an UK company as I'm in the UK.
I went into Device Manager and initially Googled for the model number of the HDD which was for a 640GB HDD.
The only one I found had one review where it said it failed after three weeks - so didn't bother with one from there.
My next step was to Google for one for the make and model of laptop and found a 1TB one almost half the price of that 640GB one and that arrived within three days of placing my order.
There is a Dism cmd you can use for the system files but I can't see the point of trying to repair a system on a failing HDD as more and more will become corrupt.
That cmd is -
dism /online /cleanup-image /restorehealth
You would normally follow that with a sfc /scannow to see if any corruption remains.
There are others as you can see from this article -
https://technet.microsoft.com/en-GB/library/hh824869.aspxThe most commonly used are /scanhealth and /checkhealth
Some have found problems when using the offline cmd with a mounted image as in the article.
Instead of using any of the full cmd offline ones with the source, you can boot up with install media and when you get to the Install screen, click on Repair your computer and navigate through the advanced boot options to select Command Prompt.
At the prompt enter bcdedit |find "osdevice"
That is a Pipe symbol before find and is the uppercase of \
Using the partition letter that gives instead of the X I have used, enter this cmd -
sfc /scannow /offbootdir=X:\ /offwindir=X:\Windows
You need to use the bcdedit cmd as it doesn't always see the volume as being in C: in this mode.
That will compare the system files from the install media and repair as necessary.
Its possible that 9GB came from either obsolete updates by cleaning out the WinSxS folder or the Windows.old folder which would have been a leftover from when you upgraded to Win 8.1 - but you would normally have to physically check its box as it wouldn't normally be default checked.
It would normally only list that and Windows Update after the Disk Cleanup's first pass and then you would need to click on Clean system files.
There is another dism cmd which will clean out the WinSxS folder which you would run before the /restorehealth one and that is -
dism /online /cleanup-image /startcomponentcleanup
This can sometimes take a while to complete and is incorporated into Shane's Windows Repair program.
It can be cancelled in the program if it does seem to be taking a very long time and holding up the rest of the repairs.