sfc - system file checker, retrieves the correct version of the file from %Systemroot%\System32\Dllcache or the Windows installation source files, and then replaces the incorrect file.
If you want to see what was replaced, right click My Computer > manage, expand event viewer > system.
System File Checker (sfc)
Scans and verifies the versions of all protected system files after you restart your computer.
There has to be a way to point it from cd prompt to the hard drive. When in doubt, Google.
Typically the "Insert CD" message has only an OK and Cancel button. Press OK, allowing it to fail. The next dialog will typically ask you to provide the location of the CD-ROM; just type in the full path of the I386 directory you discovered above.