user1497: Using bitcoin-qt, multibit, or any of the others, how do I backup and save my wallet in case I need to reinstall Windows?

user659: bitcoin-qt

open the File menu
click Backup Wallet...
select a file to save the backup as

MultiBit
From http://multibit.org/help_backupWalletUsingPrivateKeys.html:

You can export your private keys from a MultiBit wallet into a file
  (using the 'Tools | Export private keys' option) and, as long as you
  do not manually create new receiving addresses, you can use the
  private key file as a backup for the wallet.

Armory
From http://bitcoinarmory.com/index.php/start-page/what-is-armory/features:

Not only are the wallets determinstic, but there is a built-in dialog
  for printing permanent copies of your wallet.  When you first create
  your wallet, make sure your printer is on and click the “Paper Backup”
  checkbox.

Electrum
From http://electrum.org/:

You do not need to perform regular backups, because your wallet can be
  recovered from a secret phrase that you can memorize or write on
  paper.


1497: <p>Using bitcoin-qt, multibit, or any of the others, how do I backup and save my wallet in case I need to reinstall Windows?</p>
 659: <h2>bitcoin-qt</h2>

<ul>
<li>open the <code>File</code> menu</li>
<li>click <code>Backup Wallet...</code></li>
<li>select a file to save the backup as</li>
</ul>

<h2>MultiBit</h2>

<p>From <a href="http://multibit.org/help_backupWalletUsingPrivateKeys.html">http://multibit.org/help_backupWalletUsingPrivateKeys.html</a>:</p>

<blockquote>
  <p>You can export your private keys from a MultiBit wallet into a file
  (using the 'Tools | Export private keys' option) and, as long as you
  do not manually create new receiving addresses, you can use the
  private key file as a backup for the wallet.</p>
</blockquote>

<h2>Armory</h2>

<p>From <a href="http://bitcoinarmory.com/index.php/start-page/what-is-armory/features">http://bitcoinarmory.com/index.php/start-page/what-is-armory/features</a>:</p>

<blockquote>
  <p>Not only are the wallets determinstic, but there is a built-in dialog
  for printing permanent copies of your wallet.  When you first create
  your wallet, make sure your printer is on and click the “Paper Backup”
  checkbox.</p>
</blockquote>

<h2>Electrum</h2>

<p>From <a href="http://electrum.org/">http://electrum.org/</a>:</p>

<blockquote>
  <p>You do not need to perform regular backups, because your wallet can be
  recovered from a secret phrase that you can memorize or write on
  paper.</p>
</blockquote>
