My husband died recently. He had a Bitcoin-Qt wallet with some bitcoins. I don't know the password and the wallet is locked and encrypted. Is there anyway to regain access to the wallet?
Sorry for your loss.
If he used early versions of Bitcoin, he may have made an unencrypted backup of his wallet.dat file somewhere. Cracking a password may be impossible, so this might be your next best option.
Wallet encryption is a feature that was implemented in version 0.4.0 on 23rd Sep 2011, so if you do find a wallet.dat file older than that it's probably not encrypted.
Bitcoin users that are aware they are holding a substantial amount of bitcoins also are probably aware that they need to back their wallet.dat file up to a location different to their PC's hard disk in case of failure. You might find it on a DVD, thumb drive, or maybe somewhere like Google Drive.
There is a discussion about the subject, including a script for password cracking, at https://bitcointalk.org/index.php?topic=85495.0;all