If you lost the PW to your wallet you only have one chance and that are the private keys for 1. active 2. ownership of one account. If you have multiple accounts in one wallet, you need all the different keys.
You can recover one account from:
a) BrainKey plus Wallet Password
b) Wallet .bin file plus Wallet Password
c) Private Key (Active + Owner) from one Account
Once you unlocked a wallet, you can change the wallet password. If you lost your wallet password you are out of luck. If you are lucky, you might have the same account in a different wallet on a different computer. Then you can get access to the account again.
Remember, One Wallet can have several accounts.
I don't know what's the problem because I put the right password. I have only one account and one wallet. The name shows up in the right corner, but when I want to unlock the wallet it says that the pass is incorrect. If I can access the private key from the account can I change the password?