Transaction not received

[Klortho]

I'm brand new to bitcoin, and yesterday I installed the client and fired it up, and then immediately went and bought some bitcoins.  I got an email form the seller, saying "Bitcoins have shipped".  But then I realized that I was behind a firewall (at work), and my client wasn't connected.  By the time I figured out how to move my wallet to my home computer, so that I could connect to the network with the original receiver bitcoin address, a whole day had gone by. Now, I have waited (connected) about an hour, but still don't see the transaction.

Is this normal?  Does the transaction have to be acknowledged by the receiver before it gets added to a block?  If so, does the sender periodically resend the transactions?

[PLATO]

You need to download the whole blockchain before tx show up. You should see "120960" as of 04.29.11.

edit: welcome to Bitcoin! check out my Bitcoin Roadtrip: http://bitcointalk.org/index.php?topic=4752.0

[riX]

You probably don't have all blocks downloaded yet, check your receiving address balance at http://blockexplorer.com/address/insert-your-bitcoin-address-here

[Klortho]

Alas, all blocks received, still no coins (see screenshot*).  I see the balance at http://blockexplorer.com/address/17QsAdFUQYG6QNqmD3g5jmzjrfgrrod6BV. 

I wonder, could it be because I swapped wallets after the blocks had downloaded?  If I go and delete the database and re-download, the coins will show up?  Seems like there ought to be a better way.

* Nevermind about the screenshot -- forum says "uploader is full".

[riX]

Start the client with the -rescan switch. (Or with -? for more commands).

[PLATO]

Backup your wallet.dat file so if you fuck it up somehow you have a hope of getting the coins back.

The -rescan option should probably work. To use this, you will need to browse to the directory where bitcoin.exe is (in win7 it's easy, shift-right click inside the directory and click 'open command window here'), Then type bitcoin.exe -rescan at the command prompt, it should rescan the block chain and start the client.

[Klortho]

Brilliant. Thanks for the help, the rescan option works.
Thanks for the tip about the wallet backup as well -- already done!

[Odin-Zifer]

Thanks fixed my issue