First thing you want to try to do is download ccleaner, go to tools and use start-up manager- find anything in the File row that starts with D: and disable it, if nothing found then look for anything that says error or some error message like ERR.4593453.
If that doesn't work then disable anything you don't need, check under file to make sure that it does NOT say something like C:\System\ or the word system in it. Also check Program for the name of an item like for example "msnger" would be MSN messenger or windows live messenger
If all fails (i do not recommend this but if all comes to fail try it - anyways it says it doesn't work anyways, nothing ill happen) delete it by going to start>run> D:windows/ then find sfc_os.dll manually and delete it. restart your computer once and if nothing happens as it doesn't show the error message again then i recommend once it is in the recycle bin use Ccleaners recycle bin deleter ( can be used by just using a clean with Ccleaner or it should be on the right click menu of the recycle bin ) or use advanced system care's secure permanent shredder witch you have to download advanced system care and right click on the recycle bin to use
