Nobody with a Live ID on a Money file has had success getting in without remembering the email address and password.
Disconnect from the Internet. Pull your ethernet cable or turn off
your modem -- whatever it takes. Start Money, click below the
password field to select "I want to sign in to Money directly,
without access to all online services." then click Next.
While you havealready changed your LiveID, use the credentials that were in
effect at the time that you saved that Money file. Do not bother trying to use the password that you tried to switch to.
The password is case-sensitive. If you are not sure of your
credentials, write down what you remember. Consider permutations.
Check your notes. You will not get into the file without those
credentials in effect when the file was saved. Keep a pad and pencil by your bed.