Hi,
A little bit of instruction. Do not know whether would work for you.
You could open with 7zip, the OS , that now you have and depending upon your windows version, you could copy the one from the installation DVD for 64 bit. Though one has only one version of the operating system, the DVD has all version of windows, but you have to select the correct version , whether ultimate verson, etc.
The same set of windows files, as in your operating system, in the same location for example if a file is in c: windows, the same will be found in the same directory. Only thing is you have to correctly choose the version and path and then it is a matter of minutes to get the copy of any dll files in to your system.
The detailed instructions are given in this wonderful link. I have succeeded in copying some of the corrupted files in the system with my own dvd. Just you have to download 7zip, to get this done
the link is
http://www.sevenforums.com/tutorials/42776-extract-files-windows-7-installation-dvd.html You have to scrupulously follow the instruction there.
SFC scannow could correct only from the winsock or store in the downloaded os folder. If these are corrupt, then the same file will be copied from store. This is one of the alternative, which proved to be good. I have copied wanted files from the installation dvd, which have all the version on it.