The sfc /scannow is unlikely to cause you any issues compared to the issues it may be able to fix. You cannot uninstall IE8 to start from scratch, you can only disable it.
What stage are you at now.Its obvious your ghost image you mentioned already contains whatever issues are preventing the install. Do you have an image prior to that you could use.
I would get yourself back into the position where you have IE8 back. Run sfc /scannow to fix any errors, double check your pc is up to date in windows update then try again with the offline installer.