ASP: Password Validation

Hello,
In Classic ASP, I am looking for a way to implement password validation where it checks to see that the password entered is at least 8 characters, has at least 1 numeric character and at least 1 letter.

I have this code so far checking for the 8-character mininum:

if len(request.form("Password")) < 8 then
Session("ErrorMsg") = "Your password must be at least 8 characters<br>"

How can I add to this to check for the other criteria?

Thanks,
Michael