starting a letter-

[Unregistered]

when writing a letter or e-mail- after addressing the person- I use a comma-
then beginning the letter do i start with a capital letter?

[hanky]

when writing a letter or e-mail- after addressing the person- I use a comma-
then beginning the letter do i start with a capital letter?

I am not a teacher,

As far as I remember: No, you don't. On the other hand, if you use a colon (:) you should start with a Capitalized letter.