user9234: I reinstalled windows7, but luckily it saved my old windows in windows.old plus i backed up encrypted wallet to external device.  How exactly do I restore it?

user942: Be very careful. First, shutdown Bitcoin-Qt completely. Rename its current wallet.dat file to something else (you can delete it, but just rename it to be safe). Then put your backup in its place. Start Bitcoin-Qt and you're done.

9234: <p>I reinstalled windows7, but luckily it saved my old windows in windows.old plus i backed up encrypted wallet to external device.  How exactly do I restore it?</p>
 942: <p>Be very careful. First, shutdown Bitcoin-Qt completely. Rename its current wallet.dat file to something else (you can delete it, but just rename it to be safe). Then put your backup in its place. Start Bitcoin-Qt and you're done.</p>
