If you forget the password you registered for myOMRON you can request for it to be resent to you. From any myOMRON page find the "Login" panel near the top left of the page:

Fig 1: Login Panel
At the bottom of the panel, click the "Forgot Password" link. Now enter your registered email address and click the
[Lookup]
button. Your password will now be emailed to you. If it doesn't arrive within a few minutes please check your Spam folder or any anti virus quarantine areas.