There are lots of programs that can do this. We recommend the free FreeUndelete, because it’s free. It’s important not to modify the drive you want to recover data from in any way (like installing an undelete program). Any files you write to the drive can overwrite your deleted data and render it unrecoverable. That’s why it’s a good idea to do your undelete from a CD. If you’re looking for the command that will automatically replace missing system files, place your Windows disk in the drive, go to Start, click on run, type “command” and then when the command line pops up, type “sfc /scannow”.