How do I unlock a bitcoin-qt wallet? I know my passphrase and all. It says that my wallet is encrypted and locked for now so how do i unlock it?
To unlock your wallet:
Option 1: Introduce password in prompt that opens when you send coins
Option 2: Console (Help > Debug window > Console)
Type the following:
walletpassphrase "passphrase" timeout
Where passphrase is your password and timeout is the number of seconds you want the wallet unlocked (i.e. 120 = 2 min). This is option is the only one when you want to do something that requires unlocking but you don't want to send coins (like dumping a private key) or when you plan to leave the wallet open and fear forgetting to lock it again.
It unlocks when you need to spend. If you try to send money to an address, it'll ask you for a password. You don't need a password to receive bitcoins.