The outer shell will probably be pretty hard, but you should be able to repair the front grill just around the disk drive with a rubber mallet. If you can't find a rubber mallet, tie a thick cloth over a hammer and hit lightly. A heat gun might help soften the metal up a bit too. If you don't mind painting, fill in any scratches or remaining dents with epoxy (or automotive body fill) and sand. Don't worry about filling in the holes on the grill, you can use a 3mm drill bit to drill them back in. Finally paint it.