I dont quite understand how your 'origional' has become corrupt, so try uninstalling it from your machine & installing it on a friends & seeing if that workd, this will tell you if your 'Origional' is corrupt oh by the way do you mean the cd you brought is corrupt or your backup is corrupt? I recomend you download ClonyXXL to scan your CD and this program will tell you how to make a backup copy of it, by the way if you already have one backup you should destroy it as having more than one backup is breaking the EULA.