I believe Windows still sees a new hardware hash because: Even though you performed this "trick" on the same hardware, there is one item that is different, if you have freshly formatted your hard disk drive; the volume serial number. This changes with every format you perform on the drive. Windows sees this and I believe recreates a new hardware hash, which will not match up with the data that is related to your wpa backup files. Before you formatted, you should have went to a command prompt and did a "dir" command. It will then show your the Volume Serial Number. Write that down. Then find the utilty called "VolumeID". Its a small executable that will allow you to rename your drives volume serial number after you've formatted it. Once you have that renamed to what it was before you formatted, in its post-activated state; this little "backup the wpa file" trick may work.