When you run sfc /scannow and it prompts you to insert the disk it means that there are files which need to be repaired or replaced.
Do you know anyone who could loan you an XP disk to make this repair? This would be the simplest. You might call a local repair shop to see if they will burn you a copy.
Another option will be to use the i386 file. This involves editing the Registry, if mistakes are made during this it can damage your operating system. For this reason you should use a program like ERUNT
to back up your registry. If you are not comfortable doing this I would suggest trying to find a disk to borrow.
Click on start / run and type regedit in the box provided.
This starts registry editor
Each time you see " \ " it is designating the next part to be clicked on. Ex: HKEY_LOCAL_MACHINE\(click on)Software...
Navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\setup
Click on SourcePath
in the Value data box type C:\