If you do not remember the password to your old account, you can always reset it. This is not a way to recover encrypted files! It’s only to allow you to sign in to the new AxCrypt. The new password will be used to encrypt new files. Go to https://account.axcrypt.net/Home/PasswordReset to do this, or you can also go there from AxCrypt with File | Options | Password Reset .
Unfortunately, if you do not know the password you cannot open an encrypted file. That is what AxCrypt is made for!
Please check the FAQ at http://www.axcrypt.net/support/faq/ for more information.