Ah okay. I understand now. So say I have my private key in a safe place, I lost my computer or something, I can use that private key to retrieve my bitcoins?
Yes, but you still need wallet software. You will need a computer and have a wallet software on it. Then you have to import your private keys into that wallet software to make your transactions. Note that you should not be reusing addresses and their respective private keys, i.e. you should generate a new private key and move your coins there after every time you spend any of your coins.
