How can I restore my wallet? I just purchased a new laptop and I want to decommission my old one.  I have a back-up of my wallet.dat file copied to my new PC.  What do I need to do to restore it to my Bitcoin (Windows) client?  Please note, this is a wallet.dat file that is about 6 months old and I haven't loaded it in at least four months.  I'm not sure if that makes a difference or not, contingent on the original version of the client that created the file.
You need to put the old wallet.dat in your bitcoin data directory.

The default for Windows is:

C:\Documents and Settings\YourUserName\Application data\Bitcoin (XP)

C:\Users\YourUserName\Appdata\Roaming\Bitcoin (Vista and 7)


Then run the bitcoin client with the -rescan option.

Alternatively you can run the bitcoin client with the -datadir=&lt;location of backup wallet.dat&gt; as well as the -rescan option if you do not want to move/backup the new wallet.dat.

The default for Mac OS X is:

~/Library/Application\Support\Bitcoin



The default for Linux is:

~/.bitcoin