That depends on the form. If the form uses a "mailto:" call in the HTML form tag, then it will use whatever default email client you've set up. (Obviously, if OE is removed and not replaced with another email client, then this won't happen.) In all other cases, the form. tek-tips replies, etc. are sent via the browser and not the email client. On my personal machine, I have IE, Netscape, Mozilla, Firefox, and Opera as browsers but I DO NOT have OE or Outlook.
There's always a better way. The fun is trying to find it!