How do I reset my password on outlook express e mail?

outlook express said my pass word is not valid

To change the password, you have to know the current password. If you have entered what you believe to be your correct password and it's saying it's invalid, you need to contact your Internet Service Provider (ISP) to resolve the issue. They will likely ask you some test questions to verify you are the owner of the account.

If you know the current password you can go to Tools>Accounts>Mail>Properties>Servers while logged in and change it.