How can I get the private key from wallet.dat from 2011 Bitcoin software on WinXP? I set up Bitcoin (application) software on a WinXP machine in 2011 and received some Bitcoin. I set the machine aside, disconnected from the internet. Now I want to access the 2011 Bitcoin.

Lately I verified my Bitcoin address/public key on blockchain.info, and the BTC is still there. I backed up the public key and wallet.dat* onto a flash drive. The WinXP machine is functioning.

I am a former coder but new to Bitcoin under the hood, but willing and able to learn whatever is necessary to retrieve, control, and move the BTC. *I suspect that the wallet.dat file "contains" the private key, but I can't read the file contents with Notepad. 

What secure tools do I need, and what is the best way to fill my knowledge gaps so that I can resume control of the BTC?
The wallet.dat was created with Bitcoin Core (in 2011 it was called "Bitcoin").

You should install the newest version of Bitcoin-Core (0.14.2 by the time of writing). The wallet.dat from 2011 should still run.

Use the GUI.

If you want to export the private key, you don't need to sync (takes a couple of hours / days)

Can also be done on a different machine then your Windows XP box.

Following steps may help:


Start Bitcoin Core
Stop Bitcoin Core
Datadir should be created, open the datadir folder (https://en.bitcoin.it/wiki/Data_directory)
Replace the existing wallet.dat (backup it if you already had Bitcoin Core installed) with your old wallet
Start Bitcoin Core
If you want to export your keys, open the debug console and type dumpwallet &lt;filename&gt;
If you want to use Bitcoin Core, let it sync (takes a couple of hours/days)