Simply click the 'Lost Password' link
Enter your Email address registered to your CarVue account and hit Submit
You will be shown that a mail is sent to you
You will then be sent a link to your email inbox
Click the link and you will then be able to select a new password for your account.
Hit reset password, and you'll be redirected to the login screen, where you can then fill in your new password to get access back in to CarVue. You'll also receive a password reset email confirmation in your inbox.
Of course, if you remember your password, you can just ignore the email and log back in as normal