Reply feature will not work in Outlook 2003

How many e-mail accounts do you have in your computer? Perhaps one of the accounts doesn't have the outbound (SMTP) server settings correct. The reason I say this is because if we look at a hypothetical situation where you have 2 accounts (for simplicity 1 and 2) and account 1 is the "default" account. When you create a new message, account 1 is always used, unless you tell it otherwise and it sends from that one fine. But say you receive a message from account 2 and you reply, that will also use the account 2 outbound e-mail settings which might not be correct. I'd make sure you check those.

Thank you! I'll need to check that. The computer is used by 2 different people (with 2 different e-mail accounts, so that could very well be the problem!