for me it is not required to manipulate or entering the OS Systems folder. Because it contains all the information needed frm startup till all the computer capabilities and functions. if the file is not yet corrupted better place it again to the location. But if not better to boot, insert ur OS cd and restore your system. correction po, u cannot paste a file in a cd coz it is optical device. Optical device can only transfer a file using a cd burning file like Nero.